Answer:
(1) H0: The mean MPG rating of the vans is 38.8
H1: The mean MPG rating of the vans is not 38.8
(2) The significance level is 2%
(3) The test statistic is -1
(4) The test is two tailed
(5) Fail to reject H0. The mean MPG rating of the vans is 38.8
Step-by-step explanation:
(1) A null hypothesis is a statement from a population parameter which is either rejected or accepted (fail to reject) upon testing.
An alternate hypothesis is also a statement from the population parameter that negates the null hypothesis and is accepted if the null hypothesis is rejected.
(2) The level of significance is 0.02 (2%)
(3) Z = (sample mean - population mean) ÷ sd/√n
sample mean = 38.8, population mean = 39, sd = 2.2, n = 120
Z = (38.8 - 39) ÷ 2.2/√120 = -0.2 ÷ 0.2 = -1
(4) A two tailed test is identified by the inequality not equal to.
(5) P-value = 1 - cumulative area of the test statistic = 1 - 0.8413 = 0.1587
(6) Fail to reject H0 because the P-value (0.1587) is greater than the significance level (0.02).
