Solution :
Here, given :
Sample size, n = 39
Sample mean,
= 3.6
Standard deviation of the sample, s =2
The population mean,

The significance level,

a). Therefore the hypothesis is :

b). The test statics is given as :


= 1.873
c). The p- value is given by :



d). The conclusion :
In this case, the p-value is

So, we do not reject
.
Therefore, we conclude that it is not a statistically significant difference between national average time for selling a home and the mean time for selling in Greene County.