One method of testing a person's reaction time is to use an online, computer click timer test. Some students carried out a test using the method described. • Each student 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 student clicks a stop button on the screen. • The reaction time appears on the screen. A student in the class thought that boys had a faster reaction time than girls. A group of students from the class decided to repeat the test to investigate the hypothesis: Boys have a faster reaction time than girls. Another group of students decided to test the hypothesis: Right-handed people have a faster reaction time with their right hand than with their left hand. Table 1.1 shows their results. Table 1.1 student | reaction time using right hand/s | reaction time using left hand/s ---|---|--- A | 0.26 | 0.28 B | 0.23 | 0.23 C | 0.22 | 0.25 D | 0.25 | 0.22 E | 0.26 | 0.27 F | 0.24 | 0.24 G | 0.28 | 0.26 H | 0.25 | 0.30 I | 0.21 | 0.25 J | 0.26 | 0.29 K | 0.27 | 0.31 mean | 0.25 | 0.26 mode | | median | | Table 1.2 shows the probability values of t. Table 1.2 degrees of freedom | 10 | 12 | 14 | 16 | 18 | 20 | 22 | 24 | 26 | 28 | 30 | 40 | 50 | 60 ---|---|---|---|---|---|---|---|---|---|---|---|---|---|--- probability 0.05 | 2.23 | 2.18 | 2.14 | 2.12 | 2.10 | 2.09 | 2.07 | 2.06 | 2.06 | 2.05 | 2.04 | 2.02 | 2.01 | 2.00 One student noticed that the more repetitions of the online test that were carried out, the faster the reaction time. The student decided to carry out a different test to investigate the effect of repetition and feedback on the accuracy of carrying out a task. Three students each carried out a task which involved drawing straight lines, without using a ruler, on sheets of paper. The three students did the task in separate rooms. • Each student drew 20 straight lines, as close as possible to 7.5 cm long, on separate pieces of paper. • The teacher measured all the lines and recorded the lengths to the nearest 0.1 cm in a table. • The teacher gave feedback to each student by telling them the actual length of line 20. • Each student then drew another 20 lines which were measured by the teacher and recorded in the table. Table 1.3 shows the data that the teacher recorded. Table 1.3 line | length of measured line before feedback/cm | length of measured line after feedback /cm ---|---|---|---|---|--- | student 1 | student 2 | student 3 | student 1 | student 2 | student 3 1 | 7.2 | 5.0 | 7.3 | 7.9 | 7.5 | 5.2 2 | 7.5 | 4.3 | 7.4 | 7.0 | 7.2 | 5.2 3 | 7.4 | 4.0 | 7.7 | 7.5 | 7.7 | 5.2 4 | 7.5 | 3.9 | 7.9 | 7.3 | 7.6 | 4.9 5 | 8.0 | 4.2 | 8.2 | 7.0 | 7.3 | 6.3 6 | 7.5 | 4.3 | 8.8 | 7.2 | 7.7 | 6.5 7 | 7.5 | 4.0 | 8.8 | 7.0 | 7.4 | 6.3 8 | 7.2 | 4.0 | 9.5 | 7.2 | 8.0 | 6.2 9 | 7.1 | 4.4 | 9.3 | 7.0 | 7.6 | 6.2 10 | 7.4 | 3.8 | 9.0 | 7.1 | 7.2 | 5.7 11 | 7.2 | 7.9 | 9.3 | 7.0 | 7.5 | 6.7 12 | 7.4 | 4.0 | 8.8 | 7.0 | 6.8 | 6.6 13 | 7.5 | 4.2 | 9.7 | 7.6 | 7.2 | 6.6 14 | 7.5 | 4.0 | 9.7 | 8.0 | 7.6 | 6.6 15 | 7.4 | 4.2 | 10.0 | 8.0 | 7.4 | 6.4 16 | 6.5 | 4.1 | 10.0 | 8.2 | 7.4 | 6.6 17 | 6.7 | 4.4 | 9.6 | 7.9 | 7.0 | 6.5 18 | 6.8 | 4.0 | 9.8 | 8.5 | 7.5 | 6.2 19 | 7.9 | 4.2 | 9.7 | 7.8 | 7.7 | 6.9 20 | 7.5 | 4.0 | 10.2 | 7.5 | 7.6 | 6.1 mean ± s | 7.3 ± 0.36 | 4.2 ± 0.26 | 9.0 ± 0.90 | 7.5 ± 0.47 | 7.4 ± 0.27 | 6.1 ± 0.59