to measure the affect of caffeine - a legal drug- on reaction time
person being tested must sit with their arm resting on a table to avoid them moving their arm
hold a ruler vertically between their thumb and forefinger with zero level with their thumb
let go without warning and the reaction time is the number where they caught the ruler the lower the number the faster their reaction time and visa versa
repeat several times and then calculate a mean distance
repeat test after person has drunk a caffineated drink and compare the results
