Lily is not correct her answer is wrong.
Answer:
(A) T-stat = 1.82
(B) Critical value is 1.645
(C) Yes, there is sufficient evidence to reject the null hypothesis using a 0.05 significance level.
Step-by-step explanation:
(A) T-stat (z) = (sample mean - population mean) ÷ sd/√n
sample mean = 3850 bus miles
population mean = 3800 bus miles
sd = 275 bus miles
n = 100
z = (3850 - 3800) ÷ 275/√100 = 50 ÷ 275/10 = 50 ÷ 27.5 = 1.82
(B) The test is a one-tailed test. The critical value is obtained from the standard normal distribution table. The critical value using a 0.05 significance level is 1.645
(C) Null hypothesis: The bus mechanical reliability is 3850 bus miles.
Alternate hypothesis: The bus mechanical reliability is less than 3850 bus miles.
Conclusion:
There is sufficient evidence to reject the null hypothesis because the test statistic (1.82) is greater than the critical value (1.645)
16.15 because 33,60-1.30 is 32.30. 32.30 divided by 2 is 16.15
