Question

A study was conducted to determine whether an expectant mother's cigarette smoking has any effect on the bone mineral content of her otherwise healthy child. A sample of 77 newborns whose mothers smoked during pregnancy has mean bone mineral content x-bar1 = 0.098 g/cm and standard deviation s1 = 0.026 g/cm; a sample of 161 infants whose mothers did not smoke has mean x-bar2 = 0.095 g/cm and standard deviation s2 = 0.025 g/cm. Assume that the underlying population variances are equal. a. Are the two samples paired or independent? b. State the null and alternative hypotheses of the two-sided test. c. Conduct the test at the 0.05 level of significance. What do you conclude?

Answer 1

a) two samples are independent cause subject in both samples are different

b)

null hypothesis:			null 1- $\mu$ 2	=	0
Alternate Hypothesis:			null 1- $\mu$ 2	?	0

c)

for 236 df and 0.05 level ; crtiical value t= -/+ 1.97

as test statistic is not in crtiical value we can not reject null hypothesis

we do not have evidence that mother's cigarette smoking has any effect on the bone mineral content of her otherwise healthy child.