Some students wanted to determine the reaction time of a sample of people aged from 5–80 years. The students found three different methods of testing reaction time, as described in Fig. 1.1. Method 1: Ruler test • The subject rests their elbow on a table so that their wrist extends over the side. • The assessor holds the ruler vertically in the air between the thumb and first finger of the subject. • The zero mark on the ruler is lined up with the first finger of the subject. The ruler is released without warning. • As soon as the subject sees the ruler fall, they catch it as quickly as possible. • The distance the ruler falls is recorded in metres. Method 2: Computer click timer • The subject looks at a computer screen and clicks a start button on the screen and waits for the background colour to change. • As soon as the background colour changes the subject clicks a stop button on the screen. • The reaction time, in seconds, appears on the screen. Method 3: Light board test • The subject stands in front of a board with buttons arranged in a pattern. The buttons light up randomly. • As soon as a button lights up the subject presses the button to turn it off. • As soon as a button is pressed another button lights up. • The number of lights turned off in a set time is recorded. [Figure 1.1]