Another student, when carrying out the ruler experiment shown in Fig. 1, noticed that the more repetitions carried out, the faster the reaction time became.
The student decided to carry out a different experiment to investigate the effect of repetition on the accuracy of carrying out a task.
Five students, V, W, X, Y and Z were tested.
- Each student was given a picture of a star, as shown in Fig. 4.
- Each student sat at a desk so that the star was only visible in a mirror, as shown in Fig. 5.
- Each student was asked to draw between the double lines of the star when looking at it only in the mirror. Fig. 6 shows a star diagram completed by a student.
- The students recorded the number of times their lines went outside the double line of the star.
Fig. 4
Fig. 5
Fig. 6
Each student repeated the task nine times on the same day. The results are shown in Table 3.
Table 3
student |
number of times the students’ lines went outside the double lines of the star |
1 |
2 |
3 |
4 |
5 |
6 |
7 |
8 |
9 |
V |
48 |
48 |
46 |
44 |
42 |
40 |
41 |
41 |
41 |
W |
45 |
42 |
43 |
40 |
38 |
35 |
36 |
35 |
35 |
X |
38 |
37 |
34 |
32 |
31 |
30 |
28 |
38 |
28 |
Y |
31 |
30 |
31 |
29 |
44 |
28 |
26 |
25 |
25 |
Z |
41 |
40 |
38 |
37 |
35 |
35 |
33 |
33 |
32 |
(i)
Identify the independent variable in this experiment.
[1]
(ii)
Suggest the hypothesis that was tested in this experiment.
[1]
(iii)
A person walked into the room and started talking to one of the students who was carrying out the test.
Circle the result in Table 3 that was affected by this.
[1]
(iv)
One of the students had previously carried out a similar task.
Identify this student and give a reason for your answer.