Section B Answer all questions in this section. Two friends, Zvi and Bill, are conducting a natural experiment. They are collecting data by observing whether young or old people are more likely to become frustrated when trying to get on a busy train.

Mark scheme

Marking points from the official mark scheme (May/June 2021). The mark or mark type is shown in brackets.

1. [1] (Operationalise age as) 40 and under, 41 and over;
2. [1] (Operationalise age as) (Young =) under 20, (old =) over 60;
3. [2] It would be easy to distinguish who was young and who was old; because the categories are very different / people's appearance changes a lot between the two age groups;
4. [2] Because people wouldn't have to state their actual age; so (more ethical because) less invasion of privacy;
5. [2] 'under 20 and over 50 are easy to tell apart; so objective/reliable/valid';
6. [1] The DV is the variable being measured;
7. [1] Frustration (e.g. as 'pushing');
8. [1] The DV is what changes under the influence of the IV;
9. [2] Collecting data at the same time will improve standardisation/reliability; Because other variables that could affect frustration, such as how busy the busy train is, will be constant;
10. [2] It would control for variables such as how tired people are; Making the findings more valid as this won't mask the effect of age;
11. [2] Collecting data at different times will increase validity; by being sure that the only factor affecting frustration is age and not when people travel (e.g. busy times or not);
12. [2] Collecting data at different times will increase generalisability; As participant variables might vary over the day, e.g. (only younger passengers being) frustrated after work but not before;
13. [2] To get a more varied sample / make results more generalisable / make findings more representative; E.g. to avoid bias due to factors other than age (e.g. work, travelling alone or in pairs, time of travel);