I have to: Identify the null hypothesis, Ho, the alternative hypothesis H1 and either identify the sampling distribution (normal, t, chi-square) of the test statistic, or state the methods should not be used and why for the following:

Claim: The population mean is 425. Sample data: n=18, x bar = 438, s=21.3. The data were taken from a simple random sample collected from a normally distributed population with a population standard deviaion of 18.4.

I have Ho: p = 425, and H1: p < 425. Is that correct? I am sure of the test statistic since the population is less than 30?

Any help would be great!

Thanks!