Two plants can lose different amounts of water without losing water at different rates. One may be observed for longer. One may have more leaf area. A measurement may be affected by evaporation from the soil. Mathematics cannot erase those scientific limitations, but it can show exactly what the measurements mean and which comparisons are fair.
This learner’s guide follows the fictional transpiration investigation from the preceding Biology volume. We calculate mass differences, convert them into rates, compare repeated trials, examine the effects of normalising by leaf area and write conclusions that distinguish a numerical result from a proven cause. The dataset is invented, clearly labelled and fully worked.
- Use the correct SEC G3 Mathematics paper requirements for 2027.
- Calculate mass loss, units and average rates with clear working.
- Compare means, medians, ranges and percentage differences.
- Understand the purpose and the risk of normalising by leaf area.
- Evaluate graphs, rounding and uncertainty before making decisions.
Why the question must come before the calculation
A student sees two mass measurements and subtracts them immediately. That may be necessary, but it is not yet enough. Ask what the investigation is trying to compare. Is the question which plant lost more mass over a fixed interval, which lost mass more quickly or which lost more per square centimetre of leaf? These are different quantities. Each requires a different calculation or denominator.
An accurate calculator result can still answer the wrong question. The problem becomes more serious when a percentage is attached to an undefined base. A statement such as ‘transpiration was 50% higher’ must specify whether that percentage refers to raw mass loss, rate over equal time, rate per leaf area or something else.
The discipline in Mathematics begins with naming the quantity, choosing a model and checking the units. Then the arithmetic follows. The same habit helps in data-based Science and when evaluating numerical claims in English.
The correct 2027 SEC G3 Mathematics assessment
The official SEAB 2027 G3 school-candidate directory, updated on 26 October 2026, lists Mathematics as K310, with 4052 retained only as the earlier reference code. The K310 syllabus provides two written papers of 90 marks each, with two hours and fifteen minutes per paper and equal 50% weightings.
Paper 1 has about twenty-six short-answer questions. Paper 2 has nine or ten questions of varying lengths, with the final question focused on a real-world application. Candidates answer every question. The official notes say that omitting essential working may lose marks, relevant formulae will be supplied and non-exact answers should generally be given to three significant figures, with angles in degrees to one decimal place, unless the question specifies otherwise.
A transpiration table is our own teaching context. It is not an indication of a future examination question. The transferable Mathematics concerns data handling, proportional reasoning, measurement, graphical interpretation and selecting a justified method. The Science explanation remains the distinct owner of the biological concepts.
Read the initial example accurately
In Volume 1017, a fictional covered plant pot in still air begins at 820.0 g and ends at 817.2 g after forty minutes. A second pot under gentle airflow begins at 814.0 g and ends at 809.8 g over the same interval. The experiment aims to reduce direct evaporation from soil, but no claim is made that every possible source of mass loss has been perfectly removed.
For the first pot, mass loss equals initial mass minus final mass: 820.0 − 817.2 = 2.8 g. For the second, 814.0 − 809.8 = 4.2 g. The smaller initial total mass of the second pot does not by itself mean that it lost less. Its measured change is greater. When comparing changes, subtract readings for the same pot.
Clearly record the negative direction if your notation uses final minus initial mass. We can describe mass loss as the positive magnitude of decrease. Either convention can work when defined, but switching signs halfway through a solution can turn a decrease into a misleading increase.
Convert mass loss into an average rate
Rate means change divided by time. In this case, the still-air pot lost 2.8 g in forty minutes, giving 2.8 ÷ 40 = 0.070 g per minute. The gentle-airflow pot lost 4.2 g in forty minutes, giving 4.2 ÷ 40 = 0.105 g per minute. A rate requires the time unit, not merely a mass unit.
The difference in calculated average rate is 0.105 − 0.070 = 0.035 g per minute. Both measurements are averages across the forty-minute period. We do not know from these two endpoints whether mass loss occurred uniformly at every minute. Do not draw an unsupported claim about the instantaneous rate.
To express the second rate in grams per hour, multiply by sixty: 0.105 × 60 = 6.30 g per hour. This is a unit conversion of the average rate, not a prediction that the plant will continue at that rate indefinitely for an entire hour under changing conditions.
Percentage comparison: name the reference
To compare the moving-air rate with the still-air rate, choose still air as the reference because the question asks how much higher the moving-air rate is relative to the still-air value. The difference is 0.035 g per minute. Divide by the still-air rate: 0.035 ÷ 0.070 × 100% = 50%.
Thus the moving-air recorded average rate is 50% higher than the still-air average rate in this particular two-pot example. It is also 1.5 times the still-air value. These are two equivalent mathematical descriptions. It would be wrong to say the rate increased by 50 percentage points, because the rates are measured in grams per minute, not as percentages of a fixed whole.
If the reference were changed to the moving-air rate, the percentage difference would be 0.035 ÷ 0.105 × 100%, approximately 33.3%. The numerical difference is unchanged, but the percentage depends on the base. Always make the chosen base explicit.
Equal total loss can hide different rates
Suppose another plant loses 3.0 g over thirty minutes. Its average rate is 3.0 ÷ 30 = 0.100 g per minute. A fourth plant loses 3.0 g over sixty minutes, giving 0.050 g per minute. Both lose exactly 3.0 g, yet the first measured average rate is twice the second.
This is why a comparison of totals is fair only when the time intervals are the same, or when the intended question concerns the totals themselves. When the times differ, put them on a common rate basis. The unit acts like a warning label on the answer.
Do not assume that the shorter experiment had a higher underlying biological rate for reasons of treatment alone. The plants and conditions may differ. Mathematics identifies the descriptive rate; scientific design determines how far a causal interpretation is justified.
Extend the example with repeated measurements
Single observations provide a narrow view. Consider four fictional forty-minute trials in still air with recorded mass losses of 2.8, 3.2, 2.5 and 3.1 g. Four matching-duration trials under gentle airflow record 4.2, 3.8, 4.6 and 4.1 g. These additional values are invented for teaching. They do not represent measured evidence from a real laboratory.
The still-air total is 2.8 + 3.2 + 2.5 + 3.1 = 11.6 g. Dividing by four gives a mean mass loss of 2.9 g per forty-minute trial. The moving-air total is 4.2 + 3.8 + 4.6 + 4.1 = 16.7 g, giving a mean mass loss of 4.175 g per trial.
The repeated-data mean rates are 2.9 ÷ 40 = 0.0725 g per minute for still air and 4.175 ÷ 40 = 0.104375 g per minute for airflow. Report the latter as approximately 0.104 g per minute to three significant figures when a final non-exact answer is requested without another specified accuracy.
Compare the repeated-data mean rates
Subtract the unrounded rates before rounding the difference: 0.104375 − 0.0725 = 0.031875 g per minute. To three significant figures, that is 0.0319 g per minute. This result describes the difference between mean rates under the model of equal trial duration.
To express the mean airflow rate as a percentage higher than the mean still-air rate, calculate (0.104375 − 0.0725) ÷ 0.0725 × 100%. The result is approximately 44.0%. This is different from the 50% in the original two-pot comparison because we now have more observations.
A learner should not treat the two percentages as a contradiction. They are computed from different datasets. The single-pair example yields 50%, while the four-trial summary yields about 44%. Label the source of each conclusion clearly and do not silently replace the dataset halfway through an answer.
Median and range describe more than the mean
Sort the still-air losses: 2.5, 2.8, 3.1 and 3.2 g. With four values, the median is the mean of the two central values, (2.8 + 3.1) ÷ 2 = 2.95 g. The range is 3.2 − 2.5 = 0.7 g. The mean was 2.9 g, which is close to the median in this sample.
Sort the airflow losses: 3.8, 4.1, 4.2 and 4.6 g. The median is (4.1 + 4.2) ÷ 2 = 4.15 g. The range is 4.6 − 3.8 = 0.8 g. The larger range indicates a slightly wider span of observed losses in the airflow sample, but a range alone does not describe how the rest of the values are distributed.
The means, medians and ranges help readers understand the records. They do not make a four-trial set representative of every possible plant. A descriptive statistic reports what is in the sample. An explanation about environmental causes needs more than the fact that one mean is larger.
Why the mean of rates and the rate from totals can differ
When every observation lasts forty minutes, calculating each trial’s loss rate and taking the simple mean gives the same result as taking the mean loss and dividing by forty. Algebraically, dividing every measurement by the same constant commutes with taking the mean.
But suppose trial durations are twenty, forty and sixty minutes. A simple mean of three rates gives equal weight to each trial, whereas total mass loss divided by total observation time weights the longer observations more heavily. These are different summaries. The right one depends on the question.
For example, a 2 g loss in twenty minutes is 0.100 g per minute, while a 3 g loss in sixty minutes is 0.050 g per minute. Their simple mean rate is 0.075 g per minute. The combined total divided by combined time is 5 ÷ 80 = 0.0625 g per minute. Explain which interpretation you intend rather than choosing a convenient number.
Leaf area changes the comparison
A plant with more leaves may lose more water in total simply because it has more surface available. To consider a different comparison, a researcher might divide the rate by measured leaf area. This creates a normalised rate with units such as grams per minute per square centimetre. The division is mathematically simple, but the scientific assumption must be understood.
Take the first still-air pot at 0.070 g per minute with an invented measured leaf area of 100 square centimetres. Its area-normalised rate is 0.070 ÷ 100 = 0.000700 g min⁻¹ cm⁻². Suppose the moving-air pot has 125 square centimetres of leaf area and a raw rate of 0.105 g per minute. Its normalised rate is 0.105 ÷ 125 = 0.000840 g min⁻¹ cm⁻².
The raw-rate ratio is 0.105 ÷ 0.070 = 1.5, or 50% higher. The area-normalised ratio is 0.000840 ÷ 0.000700 = 1.2, or 20% higher. These statements answer different questions. Neither is universally ‘the correct effect’ without specifying what was measured, what was divided by area and why the comparison is meaningful.
Normalising does not repair an unfair experiment
Dividing by leaf area can make comparisons of different-sized plants more interpretable, but it does not eliminate every biological difference. Leaf age, stomatal distribution, water status, species and conditions can still affect the result. The leaf-area measurement itself may contain error.
Suppose the leaf-area estimate is too small for one plant. Dividing its rate by an underestimated area will make the normalised result artificially large. The calculation may be faultless given the recorded number while the measurement model remains weak. The answer should distinguish mathematical accuracy from experimental validity.
Use a normalised quantity only when the task warrants it. Sometimes the school wants total water use for a whole plant, in which case the raw rate may be relevant. Sometimes it wants a comparison of leaf surfaces, in which case normalisation helps. Clarify the question before choosing.
Check units with dimensional reasoning
Suppose mass loss is in grams and time is in minutes. Mass loss divided by time has unit g/min or g min⁻¹. If you then divide by leaf area in square centimetres, the resulting unit is g min⁻¹ cm⁻². Writing g/cm when you divided by an area would be wrong: square centimetres and centimetres represent different dimensions.
An average rate of 0.10 g/min corresponds to 6.0 g/hour because there are sixty minutes in one hour. Converting the time unit requires multiplication or division in the correct direction. A rate expressed per hour should generally be numerically larger than the same rate per minute.
Unit checks catch errors that a calculator cannot. If your answer to a mass-loss question is written in centimetres per second, something is wrong with your model or labelling. Before finalising, trace the units through every operation.
Graphs of cumulative mass loss
Suppose measurements are taken every ten minutes. A useful graph can show elapsed time on the horizontal axis and cumulative mass lost on the vertical axis. The slope between two points gives an average rate of mass loss over that interval. A steeper segment means a larger change in mass per unit time, provided the axes have comparable scales.
Do not interpret a graph of remaining total mass as if it were a graph of cumulative mass loss. In one, a downward slope can represent decreasing mass. In the other, an upward slope can represent increasing accumulated loss. The underlying physical change is the same, but the plotted quantity and sign differ.
If points are irregular, do not invent a smooth scientific law. A straight segment between adjacent points may help visualise an interval rate, but it does not prove that the instantaneous rate was constant throughout the interval. The language of the conclusion should fit the resolution of the observations.
Uncertainty is not a licence to invent error bars
A balance that reads to one decimal place may display masses such as 820.0 g. That display resolution does not, by itself, fully establish the measurement uncertainty or accuracy. Calibration, drift and handling may matter. When a problem supplies an uncertainty, follow the specified model. When it does not, avoid fabricating an exact confidence interval.
An arithmetic difference of two recorded readings can amplify the importance of measurement limitations, especially when the difference is small compared with the total mass. A claimed mass loss of 0.1 g may be fragile if the apparatus or surroundings are unstable. The correct discussion identifies the source and possible direction of error.
Use appropriate significant figures. Carry sufficient digits through intermediate calculations, and round the final non-exact answer according to the question and official K310 guidance. Do not round every small intermediate value to one significant figure and then pretend the final percentage is highly precise.
Recognise outliers without deleting them casually
Suppose one forty-minute still-air trial records 8.0 g loss while other readings are around 3.0 g. A student may call it an outlier. That observation deserves inspection: perhaps the cover came loose, the setup was disturbed or the reading was transcribed incorrectly. But a surprising value is not automatically wrong.
Write what you know. If there is documented equipment failure, the reason for excluding a reading can be explained and the data retained for review. If there is no evidence of error, deleting it solely to make the mean look more attractive is poor practice. A mathematical summary should be transparent about inclusion rules.
Comparing the mean with the median can show whether an extreme value has a strong effect. Nevertheless, a different summary does not repair the underlying experimental design. Mathematics helps diagnose the structure of the data; it cannot replace missing records or controls.
Choose a graph for the question rather than decoration
If the task compares four trial losses in two conditions, a dot plot, table or suitable grouped display may show the values directly. If it compares a measured rate over time, a line graph may reveal changes across intervals. If it compares an area-normalised rate against leaf area, label both quantities carefully and consider what relationship is being investigated.
Do not force a pie chart onto data that are not parts of one meaningful whole. Two mean rates are not slices of a single budget merely because they can be divided by their sum. A pie chart in this setting would make the interpretation less clear.
Even a correct bar chart can mislead when the vertical scale magnifies small differences. Numerical labels, stated units and a suitable axis origin help readers judge the magnitude. Graphs are arguments made with visual quantities; they must be checked as carefully as a sentence.
Use algebra to keep the model visible
Let m₀ denote initial mass, m₁ denote final mass and t denote the observation duration. Define average mass-loss rate r = (m₀ − m₁) ÷ t, when the mass decrease is taken as positive. If leaf area A is relevant and appropriately measured, define the area-normalised rate q = r ÷ A. These formulas express relationships, not hidden biological laws.
For a fair numerical comparison, identify which symbols correspond to each experimental condition. If t differs between trials, keep each time variable separate. If the measurement concerns volume rather than mass, do not substitute the volume directly into a mass formula without an appropriate relation and information about density.
Symbols help prevent accidental swapping of readings. State the definition in words before substituting. Then show the numbers with units, calculate and interpret. A tidy algebraic line is more valuable than an unexplained answer from a calculator.
What Paper 2 problem-solving asks of your habits
The K310 Paper 2 final problem focuses on application in a real-world context. This does not mean a particular plant experiment will appear. It means students should be ready to read a context, select useful mathematical information and interpret their answer. The relevant numbers may be buried in a longer description, and not every detail will belong in the calculation.
A sound method is to define the quantity sought, record the data that matter, use the correct operation and write the result back in the context. A complete answer might say, ‘The recorded mean mass-loss rate was approximately 0.104 g per minute under airflow, which is about 44.0% higher than the still-air mean in these four-trial records.’
That interpretation is specific and bounded. It does not add that the fan caused the difference without referring to controls. The Mathematics response and the scientific conclusion work together while remaining conceptually distinct.
Find the first error rather than redoing everything
When an answer is wrong, trace the work from the question. Did the student subtract final minus initial but treat the negative as a positive gain without saying so? Did they divide by forty minutes or by four replicates at the wrong stage? Did they use the moving-air rate instead of the still-air rate as percentage reference?
Once the first incorrect operation is identified, repair the principle. A student who repeatedly mistakes percent higher for percentage points needs a lesson on reference values, not fifty more mixed worksheets. A student who omits units needs to carry dimensions through calculations.
Keep an error log by category: wrong variable, wrong denominator, unit conversion, arithmetic, rounding, graph interpretation or overclaim. Reviewing a specific category is efficient because the same error can reappear in many contexts.
A focused two-week practice sequence
Begin by solving five mass-difference questions and five rate questions with varied time units. Check that each answer names the measured quantity. Then practise percentages with both reference directions. The aim is to see why a difference divided by one base is not the same percentage as a difference divided by the other.
Next, analyse four- or five-value data sets. Calculate means and medians without deleting any observation. Plot suitable graphs and write one sentence explaining each trend. After that, introduce normalisation by a measured area and consider how its interpretation differs from a raw quantity.
Finish with unfamiliar real-world settings: drying fabric, fuel consumption, travel speed or water flow. The surface story changes, but the core questions remain: what changed, over what interval, relative to which reference and with what valid conclusion? Continue to the Science syllabus for the mechanism rather than forcing a calculator result to explain biology.
Connect earlier subjects without duplicating their jobs
The biological process is explained in Volume 1017. The earlier Volume 1014 shows why paired changes matter in plant growth data; that is a useful mathematical bridge. Volume 1016 shows how correct figures can still support a misleading public message.
For English explanation and spoken interaction, revisit Volume 1015. For families making the move beyond primary school, the Sengkang G3 after-PSLE guide gives background. These links serve distinct questions rather than sending every reader through an unrelated chain.
The lesson across subjects is simple. Biology tells us what a measurement may represent. Mathematics tells us how to compare the measurements. English helps us explain the result accurately. None should be asked to do the entire job of the other.
Twenty-four numerical diagnostic challenges
Use the following original prompts as short exercises after studying the full worked example. For every challenge, write the formula or comparison in words, show the arithmetic when appropriate, and check whether your concluding statement stays within the evidence.
1. A pot loses 5 g in fifty minutes
Divide 5 by 50 to obtain 0.10 g/min. Write the time unit in the denominator; 5 g is a total, not a rate.
To earn confidence, explain why the calculation answers this particular question. If the biological cause was not tested fairly, report the numerical comparison without claiming that the treatment has been proved responsible.
2. Two pots each lose 4 g over different times
Compute both rates with their own denominators. Equal mass loss does not imply equal rate when time intervals differ.
To earn confidence, explain why the calculation answers this particular question. If the biological cause was not tested fairly, report the numerical comparison without claiming that the treatment has been proved responsible.
3. A moving-air rate is 0.12 g/min against 0.08 g/min
Compute (0.12−0.08)/0.08 × 100% = 50%. The still-air reference must be named; do not report 50 percentage points.
To earn confidence, explain why the calculation answers this particular question. If the biological cause was not tested fairly, report the numerical comparison without claiming that the treatment has been proved responsible.
4. The reference is reversed
Compute (0.12−0.08)/0.12 × 100% = 33.3%. The absolute difference is the same while the percentage changes with the base.
To earn confidence, explain why the calculation answers this particular question. If the biological cause was not tested fairly, report the numerical comparison without claiming that the treatment has been proved responsible.
5. A pot begins at 950.0 g and ends at 944.5 g
Report 5.5 g mass loss. Subtraction is between the readings of the same pot, not between different pots.
To earn confidence, explain why the calculation answers this particular question. If the biological cause was not tested fairly, report the numerical comparison without claiming that the treatment has been proved responsible.
6. A trial lasts one and a half hours
Convert to ninety minutes before dividing. Mixing hours and minutes in a rate formula creates a unit error.
To earn confidence, explain why the calculation answers this particular question. If the biological cause was not tested fairly, report the numerical comparison without claiming that the treatment has been proved responsible.
7. A data sheet gives daily totals
Identify whether daily rates or cumulative totals are requested. The graph type and denominator depend on that distinction.
To earn confidence, explain why the calculation answers this particular question. If the biological cause was not tested fairly, report the numerical comparison without claiming that the treatment has been proved responsible.
8. One plant has double the leaf area
Consider both raw and area-normalised rates. Dividing by area changes the question and may reveal a different numerical comparison.
To earn confidence, explain why the calculation answers this particular question. If the biological cause was not tested fairly, report the numerical comparison without claiming that the treatment has been proved responsible.
9. Leaf area is measured in square centimetres
Use cm² in the denominator. Do not use cm where an area rather than a length is needed.
To earn confidence, explain why the calculation answers this particular question. If the biological cause was not tested fairly, report the numerical comparison without claiming that the treatment has been proved responsible.
10. A student rounds an intermediate rate severely
Keep working precision then round the final answer. Early rounding can change a small percentage difference enough to affect the stated answer.
To earn confidence, explain why the calculation answers this particular question. If the biological cause was not tested fairly, report the numerical comparison without claiming that the treatment has been proved responsible.
11. A balance shows only one decimal place
Avoid claiming unlimited measurement precision. Display resolution alone does not prove instrument accuracy.
To earn confidence, explain why the calculation answers this particular question. If the biological cause was not tested fairly, report the numerical comparison without claiming that the treatment has been proved responsible.
12. One trial records a surprising value
Investigate rather than delete it automatically. Report inclusion choices transparently; a tidy mean is not a reason to exclude data.
To earn confidence, explain why the calculation answers this particular question. If the biological cause was not tested fairly, report the numerical comparison without claiming that the treatment has been proved responsible.
13. Four trials have uneven durations
Distinguish the simple mean of rates from total loss divided by total time. The former weights trials equally while the latter weights observation time.
To earn confidence, explain why the calculation answers this particular question. If the biological cause was not tested fairly, report the numerical comparison without claiming that the treatment has been proved responsible.
14. A graph shows remaining mass
Expect a descending trajectory if mass is decreasing. Do not call the descending line negative transpiration.
To earn confidence, explain why the calculation answers this particular question. If the biological cause was not tested fairly, report the numerical comparison without claiming that the treatment has been proved responsible.
15. A graph shows cumulative loss
Expect an ascending trajectory when loss accumulates. Interpret the slope using the plotted quantity, not by copying an explanation from another graph.
To earn confidence, explain why the calculation answers this particular question. If the biological cause was not tested fairly, report the numerical comparison without claiming that the treatment has been proved responsible.
16. The class asks for a median of four values
Sort and average the two middle observations. The median of an even-sized set is not simply the second observation.
To earn confidence, explain why the calculation answers this particular question. If the biological cause was not tested fairly, report the numerical comparison without claiming that the treatment has been proved responsible.
17. Two samples have the same mean
Inspect spread and individual values before claiming similarity. Averages alone can conceal important distribution differences.
To earn confidence, explain why the calculation answers this particular question. If the biological cause was not tested fairly, report the numerical comparison without claiming that the treatment has been proved responsible.
18. A table omits the treatment names
Add meaningful row labels to preserve the comparison. A perfectly calculated result is unusable if the reader cannot identify which condition produced it.
To earn confidence, explain why the calculation answers this particular question. If the biological cause was not tested fairly, report the numerical comparison without claiming that the treatment has been proved responsible.
19. A graph begins just below the smallest recorded value
Check whether the visual magnifies differences. If the axis is truncated, explain the choice and give direct numerical context.
To earn confidence, explain why the calculation answers this particular question. If the biological cause was not tested fairly, report the numerical comparison without claiming that the treatment has been proved responsible.
20. A question asks which method is ‘best’
State the criterion that makes the method suitable. The answer may differ depending on whether total water use or rate per unit area matters.
To earn confidence, explain why the calculation answers this particular question. If the biological cause was not tested fairly, report the numerical comparison without claiming that the treatment has been proved responsible.
21. A student assumes every minute has the average rate
Distinguish interval average from instantaneous change. Two endpoint measurements cannot establish a constant within-interval rate.
To earn confidence, explain why the calculation answers this particular question. If the biological cause was not tested fairly, report the numerical comparison without claiming that the treatment has been proved responsible.
22. A student treats a higher measured rate as proof of airflow effect
Separate descriptive numerical comparison from causal inference. The Mathematics result is real for the supplied observations, but experimental controls govern a causal claim.
To earn confidence, explain why the calculation answers this particular question. If the biological cause was not tested fairly, report the numerical comparison without claiming that the treatment has been proved responsible.
23. A school wants a one-sentence result
Give magnitude, unit, group and limitation. A concise conclusion can be accurate without reproducing every intermediate calculation.
To earn confidence, explain why the calculation answers this particular question. If the biological cause was not tested fairly, report the numerical comparison without claiming that the treatment has been proved responsible.
24. A pupil compares g/hour with g/min without conversion
Put both rates in the same units before comparing. Unit harmonisation is required for meaningful division, subtraction and percentage claims.
To earn confidence, explain why the calculation answers this particular question. If the biological cause was not tested fairly, report the numerical comparison without claiming that the treatment has been proved responsible.
Frequently asked questions
Why do we calculate a rate? A rate compares change with time, so records taken over different durations can be expressed on a common temporal basis.
Is normalised mass-loss rate better than raw mass-loss rate? It answers a different question. The right measure depends on the investigation and the reliability of the leaf-area estimate.
Does a larger sample prove cause? No. More observations can improve description, but poor controls can still make causal inference weak.
What rounding should I use in the SEC Mathematics paper? The official K310 guidance generally requests three significant figures for non-exact numerical answers, or the specific accuracy stated in the question.
What if I calculate the correct percentage using the wrong reference? It may answer the opposite comparison. State the reference value clearly before dividing.
Official reference and next reading
For codes, assessment and rounding instructions use the 2027 G3 SEAB school-candidate directory and Mathematics K310 syllabus. For the plant-science explanation return to Volume 1017. These values and tasks are original educational examples, not official examination questions.
