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. Case Study 14-1

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 n1-1
Relatively stress free	26	31	25	26	30 n2-1

__ 8. Refer to Case Study 14-1. The obtained value of the appropriate statistic is _________.

a.	tobt = -4.73
b.	tobt = -4.71
c.	tobt = -3.05
d.	tobt = -0.47

____ 9. Refer to Case Study 14-1. The df for determining t_crit are _________.

a.	4
b.	9
c.	8
d.	3

____ 10. Refer to Case Study 14-1. Usinga = .05_{2 tail}, t_crit = _________.

a.	+2.262
b.	+2.306
c.	2.262
d.	2.306

____ 11. Refer to Case Study 14-1. Usinga = .05_{2 tail}, your 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

12. (1 points) Using the data above calculate omega squared

13. (2 points) Using the data above calculate cohen's d