Kyle conducted an investigation into doodling during lessons by boys and girls. He counted the number of doodles and how much paper was used per hour when doodling. He had several concerns about uncontrolled variables in his study.

Mark scheme

Marking points from the official mark scheme (Oct/Nov 2018). The mark or mark type is shown in brackets.

1. [2] 1 mark for quantitative data is numerical.
2. 2nd mark for Kyle's data (count of doodles / area of doodles [in cm²]).
3. [3] 1 mark for type of variable.
4. 2 marks for explanation.
5. ∞ (how interesting the lesson is could be) a situational variable
6. ∞ because it is a feature of the experimental setting, i.e. the lesson
7. ∞ because students might doodle less in these lessons / might doodle more in other lessons
8. ∞ so it would look like boys doodled less / girls would seem to doodle more.
9. ∞ so there would be an apparent gender difference (that did not exist / that was due to an uncontrolled variable)
10. [3] 1 mark for type of variable.
11. 2 marks for explanation.
12. ∞ (tiredness could be) a participant variable
13. ∞ because it is internal to the individuals
14. ∞ it might make the girls doodle more / less than they would normally
15. ∞ so there would be an apparent gender difference (that did not exist / that was due to an uncontrolled variable)