problem-8.9

problem-8.9  The test must be done by hand, as the data is summarized.
> xbar = 58260; n = 25; sd = 3250
> mu = 55000; SE = sd/sqrt(n)
> T = (xbar - mu)/SE
> T
[1] 5.015
> pt(T, df=n-1, lower.tail=FALSE)
[1] 1.999e-05
    
The significance test has a small p-value.