Question

You are a biomedical researcher and you want to know if the consumption of alcohol during

pregnancy affects the birthweight of babies. You know that the average birthweight for babies in the U.S. is m = 7.5 pounds. You draw a random sample of 16 infants whose mothers indicated that they regularly consumed alcohol during pregnancy. The sample had a mean of 6.50 and a standard deviation of 1.50.

a.            State the null hypothesis.

b.            Identify the appropriate statistical test

c.             Calculate the appropriate test statistic. Make sure to report the degrees of freedom for

the statistical test (if appropriate). You must show your work to receive full credit.

d.            State your conclusions (use a two-tailed test with a = .05 for all tests).

e.            Compute an effect size.

Answer 1

Solution-A:

Ho:

Ha:

Soution-B;

since population standard deviation is not known and n=16

perform t test for mean

Solution-c:

t=xbar-mu/s/sqrt(n)

=(6.50-7.50)/(1.50/sqrt(16))

t= -2.666667

df=n-1=16-1=15

p value for two tail t test is

=T.DIST.2T(2.666667,15)

=0.017595141

p<alpha

Reject Ho

Solution-d:

there is suffcient statistical evidence at 5% level of significance to conclude that

the consumption of alcohol during

pregnancy affects the birthweight of babies.