03:59
Intro Stats / AP Statistics
A professor of women's studies is interested in determining if stress affects the menstrual cycle. Ten women are randomly sampled for an experiment and randomly divided into two groups. One of the groups is subjected to high stress for two months while the other lives in a relatively stress-free environment. The professor measures the menstrual cycle (in days) of each woman during the second month. The following data are obtained.
High stress:
20
23
18
19
22
Relatively stress-free:
26
31
25
26
30
1. Assume you are evaluating H0 using the t-test. The degrees of freedom (df) for determining t crit are _________.
a) 4
b) 9
c) 8
d) 3
e) 2
2. Assume you are evaluating H0 using the t-test with a = 0.05, 2-tail. The correct conclusion is _________.
a) Accept H0; stress does not affect the menstrual cycle.
b) Retain H0; we cannot conclude that stress affects the menstrual cycle.
c) Retain H0; stress affects the menstrual cycle.
d) Reject H0; stress affects the menstrual cycle.
3. The obtained value of the appropriate statistic for evaluating H0 is _________.
a) tobt = -4.73
b) tobt = -4.71
c) tobt = -3.05
d) tobt = -0.47