Find p value and critical value.
Information from AAA indicates that the mean age of passenger cars in the US is 8.4 years. A sample of 40 cars in the student lots at the local university showed the mean age to be 9.2 years. The standard deviation of this sample was 2.8 years. At the .01 significance level can we conclude the mean age is more than 8.4 years for the cars of university students?
a. What is p-value?
b. What is the critical value of the test statistic?