Give the formula for test statistic and p(type 1 error).
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 mean age to be 9.2 years. The standard deviation of this sample was 2.8 years. At the .01 significance level can we end the mean age is more than 8.4 years for the cars of university students?
1. What is the probability of a type I error?
2. Give the formula for the test statistic.
3. Work out the value of the test statistic
4. What is the critical value of the test statistic?
5. Compute the value of the test statistic.
6. What is your decision regarding the null hypothesis?
7. Interpret your decision from part e in a single sentence.