It has long been theorized that mating preferences in many animal groups are driven by a need for offspring to survive and pass on genetic material. In humans this manifests itself when we often see women pursuing older (more secure) men and men pursuing younger (more fertile) women. If this is true, then we should see a tendency for older men to marry younger women. A random sample of 12 married couples was drawn from the population of married couples in the US. The ages of the husbands and wives are shown below. Test the hypothesis that women tend to marry men significantly older than them.

1. What type of hypothesis test should be used?

2. Based on the question above, should a one-tailed or two-tailed test be used?

3. State your hypotheses HINT: husband - wife

4. Find the critical region

5. Compute the test statistic

a) Calculate M_D

Couple	Husband	Wife	Difference (husband - wife)
1	49	36	13
2	74	57	17
3	69	58	11
4	43	59	-16
5	40	22	18
6	34	23	11
7	43	48	-5
8	31	27	4
9	45	24	21
10	46	42	4
11	61	62	-1
12	50	48	2
	M =	M =	MD=

b)Test statistic (s_MD= 3.39) =

6. Make a decision

7. Interpret the results

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A research study was conducted to examine the differences between older and younger adults on perceived life satisfaction. A pilot study was conducted to examine this hypothesis. Ten older adults (over the age of 70) and ten younger adults (between 20 and 30) were give a life satisfaction test (known to have high reliability and validity). Scores on the measure range from 0 to 60 with high scores indicative of high life satisfaction; low scores indicative of low life satisfaction.

1. What type of hypothesis test should be used?

2. Based on the question above, should a one-tailed or two-tailed test be used?

2. State your hypotheses ( = .05)

3. Find the critical region

4. Compute the test statistic

a) Find the two sample means:

Older Adults	Younger Adults
45	34
38	22
52	15
48	27
25	37
39	41
51	24
46	19
55	26
46	36
M1=	M2=

b)Calculate test statistic (s_(M1-M2) = 3.85):

5. Make a decision

6. Interpret the results