# Ecology - Science calculations

Maths questions often start with the command words 'calculate' or 'determine'. They will then have a blank space for you to show your working. It is important that you show your working; don't just write the answer down. Calculation errors carried forward are worked through to give credit for later working.

In some maths questions you will be required to give the units. This may earn you an additional mark. Don't forget to check whether you need to do this. Take extra care when converting between units.

Maths questions might include graphs and tables as well as calculations. Don't forget to take a ruler and scientific calculator.

If drawing graphs, make sure you:

1. put the independent variable on the x-axis and the dependant variable on the y-axis
2. construct regular scales for the axes
3. label the axes appropriate
4. plot each point accurately
5. decide whether the origin should be used as a data point
6. draw a straight or curved line of best fit

If you are asked to calculate an answer and it has lots of decimal places, don't forget to use the same number of significant figures as the data in the question. For example, if two significant figures are used in the question, then usually your answer would also be to two significant figures. Don’t forget to check your rounding.

These questions have been written by a Bitesize consultant as a suggestion to the type of questions that may appear in an exam paper.

## Sample question 1 – Foundation

Question

Two students recorded the number of birds they saw in one hour in two gardens.

The owners of garden A put out food on their bird table every day for five days. The owners of garden B moved out a month ago. No food has been put out in garden B in the last month. On day 5 they couldn't get into garden B so no results were recorded.

Day 1Day 2Day 3Day 4Day 5
Garden A75454

Calculate the mean for both gardens. [2 marks]

To calculate a mean all the values must be added up and then divided by the total number of values.

Garden A: 7 + 5 + 4 + 5 + 4 = = 5

Garden B: 1 + 2 + 1 + 2 = = 1.5. To use the same number of significant figures as the original data the answer 1.5 should be rounded up to 2

## Sample question 2 - Foundation

Question

The table shows the results from student A.

11
23
34
42
52
61

What is the median result? Tick one box. [1 mark]

 A 1 2 3 4
 A B 1 2 ✔ 3 4

To calculate this to place the set of numbers in increasing order of size. The median is the middle number. In increasing order of size: 1,1,2,2,3,4. The answer is therefore 2.

## Sample question 3 - Higher

Question

A student collected the following table of results in an investigation into the percentage of woodlice found in different conditions. Calculate the mean, median and mode for each condition.

DayDry and light (%)Dry and dark (%)Damp and light (%)Damp and dark (%)
1231562
2431362
3222868
4731854
56301153
Mean
Median
Mode
DayDry and light (%)Dry and dark (%)Damp and light (%)Damp and dark (%)
1231562
2431362
3222868
4731854
56301153
Mean4.229759.8
Median431862
Mode231862