Stress levels were recorded during a true answer and a false answer given by each of six people in a study of lie-detecting equipment, based on the idea that the stress involved in telling a lie can be measured. The results are shown in Table 10.7.5.
a. Was everyone€™s stress level higher during a false answer than during a true answer?
b. Find the average stress levels for true and for false answers. Find the average change in stress level (false minus true).
c. Find the appropriate standard error for the average difference. In particular, is this a paired or an unpaired situation?
d. Find the 95% two-sided confidence interval for the mean difference in stress level.
e. Test to see if the average stress levels are significantly different. If they are significantly different, are they significantly higher or lower when a false answer is given?
f. Write a paragraph interpreting the results of this test. In particular, is this a conclusion about these six people or about some other group? Also, how can you find a significant difference when some individuals had higher stress and some had lower stress for the false answer?

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TABLE 10.7.5 Vocal Stress Level Person True Answer False Answer 12.8 8.5 3.4 5.0 10.1 11.2 13.1 9.6 4.8 4.6 11.0 12.1