Discussion:
Q: Assume that a simple random sample has been selected from a normally distributed population. Find the null and alternative hypotheses, test statistic, P-value (or range of P-values), critical value(s), and state the final conclusion.
Claim: The mean life span of desktop PCs is less than 7 years.
Sample data: n = 21, = 6.8 years, s = 2.4 years. The significance level is α= 0.05.