Question

Breast feeding sometimes results in a temporary loss of bone mass as calcium is depleted in the mother's body to provide for milk production. An investigation gave the following data on total body bone mineral content (g) for a sample of mothers both during breast feeding (B) and in the postweaning period (P).

Subject	1	2	3	4	5	6	7	8	9	10
B	2385	2726	2357	2379	2696	2249	2067	2285	2044	2609
P	2463	2883	2381	2519	2745	2303	2157	2306	2060	2789

Do the data suggest that true average total body bone mineral content during postweaning exceeds that during breast feeding by more than 25 g? State and test the appropriate hypotheses using a significance level of 0.05. (Use a statistical computer package to calculate the P-value. Use μ_d = μ_P − μ_B. Round your test statistic to two decimal places and the P-value to three decimal places.)

t=____

df= ____

p= ____

2) A researcher at a medical college conducted a study of 60 randomly selected male soccer players and concluded that frequently "heading" the ball in soccer lowers players' IQs. The soccer players were divided into two groups, based on whether they averaged 10 or more headers per game. Mean IQs were reported in the article, but the sample sizes and standard deviations were not given. Suppose that these values were as given in the accompanying table. (Use a statistical computer package to calculate P.)

	n	Sample Mean	Sample sd
Fewer Than 10 Headers	35	112	10
10 or More Headers	25	103	8

t= ____

df= ___

p= _____

Answer 1

Question 2:

1) Null and Alternative Hypothesis:

H0: frequently "heading" the ball in soccer not lowers players' IQs.

i.e. H0: Mu1 = Mu2

H1: frequently "heading" the ball in soccer lowers players' IQs.

i..e H1: Mu1 > Mu2

2) Decision Rule:

Reject H0 if P-value < alpha 0.05

3) Test Statistic:

4) Degrees of freedom: 35+25-2 = 60-2 = 58.

5) P-Value: 0.0002

since P-value < alplha 0.05 so we reject H0

Thus we conclude that frequently "heading" the ball in soccer lowers players' IQs.