Question

A report states that the cost of repairing a hybrid vehicle is falling even while typical repairs on conventional vehicles are getting more expensive. The most common hybrid repair, replacing the hybrid inverter assembly, had a mean repair cost of $3,927 in 2012. Industry experts suspect that the cost will continue to decrease given the increase in the number of technicians who have gained expertise on fixing gas-electric engines in recent months. Suppose a sample of 100 hybrid inverter assembly repairs completed in the last month was selected. The sample mean repair cost was $3,750 with the sample standard deviation of $600. Complete parts (a) and (b) below. a. Is there evidence that the population mean cost is less than $3,927? (Use a 0.10 level of significance.) State the null and alternative hypotheses Type integers or decimals.) Enter your answer in the edit fields and then click Check Answer parts remaining Clear All Check Answer

b. determine the p value and interprete its meaning

Answer 1

The null hypotheses and alternative hypotheses to be tested are as follows.

H0: μ ≥ 3927
Ha: μ < 3927