statistics
posted by emily .
if the null hypothesis is that the mean is 3218, the alternative hypothesis is that the mean > 3228, and the sample mean is x= 3342, the sample standard deviation is s=287, the sample size is n= 42, and α= 0.01
a. calculate the z test statistic.
b. what is the pvalue?
c. would this null hypothesis be rejected or not? justify answer with the pvalue.

Z = (mean1  mean2)/standard error (SE) of difference between means
SEdiff = √(SEmean1^2 + SEmean2^2)
SEm = SD/√n
If only one SD is provided, you can use just that to determine SEdiff.
Find table in the back of your statistics text labeled something like "areas under normal distribution" to find the proportion related to the Z score.