General exam questions

Question 1

Scientists have recorded the percentage of adults who are lactose intolerant in different countries. Explain the advantage of using percentages in this type of study.

Answer 1

1. Allows comparison;
2. (As) different countries
   have different population/
   sample sizes;

Question 2

The doctors used a statistical test to compare the results for AD and LD.
They obtained a value for P of 0.047.
What does this result show about the difference between the means for AD and LD?
Use the words probability and chance in your answer. (2)

Answer 2

1. Probability of obtaining this difference by
   chance;
2. Is less than 5%/less than 0.05/less than one in
   twenty;
3. Difference is significant;

Question 3

What measurements would the scientists have made in order to calculate the rate of
carbon dioxide production? (2)

Answer 3

All three of following = 2 marks;;
Two of them = 1 mark;
Volume of carbon dioxide given off
(From known) area/ per m2
/m-2
In a known/set time

Question 4

The scientists calculated the mean rate of carbon dioxide production of the leaves
using measurements of carbon dioxide release in the dark.
Explain why they did not use measurements taken in the light. (2)

Answer 4

1. (In the light) photosynthesis/in the dark no
   photosynthesis;
2. (In light,) carbon dioxide (from respiration) being
   used/taken up (by photosynthesis);

Question 5

EQ

The wolf numbers are given per unit area. Explain why. (2)

Answer 5

Allows comparison;

Different (sized) areas covered;