Five volunteers investigate the effect of caffeine on reaction time using the falling ruler test.
Each volunteer is tested on two separate days at the same time of day. The same ruler, hand and starting position are used. Each value in the table is the mean catch distance from ten drops.
Without caffeine, the ruler is released without warning. After the volunteer has consumed caffeine, the person releasing the ruler says "ready" immediately before every release.
| Volunteer | Mean catch distance without caffeine (cm) | Mean catch distance after caffeine (cm) |
|---|---|---|
| A | 20 | 15 |
| B | 22 | 17 |
| C | 18 | 14 |
| D | 24 | 18 |
| E | 21 | 16 |
Calculate the mean decrease in catch distance after consuming caffeine.
Evaluate the conclusion that caffeine caused the volunteers' reaction times to become shorter.
135 exam-style questions on OCR GCSE Biology 3.1 Coordination and control – the nervous system, covering 3.1.1 Structure of the nervous system, 3.1.2 Coordinated response, 3.1.3 The reflex arc, 3.1.4 Structure of the eye, 3.1.5 Defects of the eye, 3.1.6 Structure and function of the brain, 3.1.7 Difficulties of investigating brain function, and 3.1.8 Limitations in treating nervous system damage. Each one has a worked solution and a mark scheme showing where the marks go.