In a study of hypnotic suggestion, 16 male volunteers were randomly allocated to an experimental group and a control group. Each subject participated in a two-phase experimental session. In the first phase, respiration was measured while the subject was awake and at rest. In the second phase, the subject was told to imagine that he was performing muscular work, and respiration was measured again.
For subjects in the experimental group, hypnosis was induced between the first and second phases; thus, the suggestion to imagine muscular work was "hypnotic suggestion" for control subjects. The accompany table shows the measurements of total ventilation (liters of air per minute per square meter of body area) for all 16 subjects.
(a) Use a t test to compare the mean resting values in the two groups. Use a non-directional alternative and let alpha = 0.05.
(b) Use suitable paired and unpaired t-test to investigate (i) the response of the experimental group to suggestion; (ii) the response of the control group to suggestion; (iii) the difference between the responses of the experimental and control groups. Use directional alternatives (suggestion increases ventilation, and hypnotic suggestion increases it more than waking suggestion) and let alpha=0.05for each test.
|
EXPERIMENTAL GROUP
|
CONTROL GROUP
|
|
SUBJECT
|
REST
|
WORK
|
SUBJECT
|
REST
|
WORK
|
|
1
|
5.74
|
6.24
|
9
|
6.21
|
5.50
|
|
2
|
6.79
|
9.07
|
10
|
4.50
|
4.64
|
|
3
|
5.32
|
7.77
|
11
|
4.86
|
4.61
|
|
4
|
7.18
|
16.46
|
12
|
4.78
|
3.78
|
|
5
|
5.60
|
6.95
|
13
|
4.79
|
5.41
|
|
6
|
6.06
|
8.14
|
14
|
5.70
|
5.32
|
|
7
|
6.32
|
11.72
|
15
|
5.41
|
4.54
|
|
8
|
6.34
|
8.06
|
16
|
6.08
|
5.98
|
(c) Repeat the investigations of part (b) using suitable nonparametric tests (sign and Wilcoxon-Mann Whitney tests).