Question

90) The Department of Transportation would like to test the hypothesis that the average age of cars on the road is less than 12 years. A random sample of 45 cars had an average age of 10.6 years. It is believed that the population standard deviation for the age of cars is 4.1 years. The Department of Transportation would like to set a = 0.05.

Answer 1

solution : - Given! - Mean (1) = 12 years. Sample mean 18 = 10 6 years. Population std devi(o) = 401 years. sample size (n) = 45 -0.05. Hypothesis | Test statistic HO:ll = 12 T y ll 10.6 - 12 Hill sizz -411 14s 1 (Left tailed test) → (left tailed test) By using '2' table at x = 0.05 Zcritical (2c) = -10645. IP-value → ng standard Normal table, P(Z <-2.29) = 0.0110 Decision of (0.05) since, p-value (0.0 110) < Reject Ho Conclusion Therefore, there is enough evidence to Claim that the aug age of caris on the road is less than 12 years at a = 0.05.