Q 69

The owner of a large car dealership believes that the financial crisis decreased the number of customers visiting her dealership.The dealership has historically had 800 customers per day.The owner takes a sample of 100 days and finds the average number of customers visiting the dealership per day was 750.Assume that the population standard deviation is 350.The value of the test statistic is ____________.
A) z = -1.429
B) t_{99} = -1.429
C) z = 1.429
D) t_{99} = 1.429

Q 70

The owner of a large car dealership believes that the financial crisis decreased the number of customers visiting her dealership.The dealership has historically had 800 customers per day.The owner takes a sample of 100 days and finds the average number of customers visiting the dealership per day was 750.Assume that the population standard deviation is 350.At a 5% significance level,the critical value(s)is(are)___________.
A) 1.645
B) -1.645
C) -1.96 and 1.96
D) -2.030 and 2.030

Q 71

The owner of a large car dealership believes that the financial crisis decreased the number of customers visiting her dealership.The dealership has historically had 800 customers per day.The owner takes a sample of 100 days and finds the average number of customers visiting the dealership per day was 750.Assume that the population standard deviation is 350.At the 5% significance level,the decision is to ___________.
A) reject H_{o};we can conclude that the mean number of customers visiting the dealership is significantly less than 800
B) reject H_{o};we cannot conclude that the mean number of customers visiting the dealership is significantly less than 800
C) do not reject H_{o};we can conclude that the mean number of customers visiting the dealership is significantly less than 800
D) do not reject H_{o};we cannot conclude that the mean number of customers visiting the dealership is significantly less than 800