Question

1. A sample of 64 ATM transactions shows a mean transaction time of 65 seconds with a sample standard deviation of 12 seconds. When testing whether the mean transaction time is greater than 60 seconds, what is the test statistic?

Select one:

a. 0.42

b. 1.50

c. 2.50

d. 3.33

e. none of the above

2. Given your answer to question 1, which of the following do we know for sure about the conclusion to a two-tailed hypothesis test at a 0.01 significance level?

(Hint: Start by finding your critical value.)

Select one:

a. a correct decision has been made

b. a Type II error has not been made

c. a Type I error has not been made

d. either a Type I error or Type II error has been made

Answer 1

Question 1

The test statistic formula is given as below:

t = (Xbar - µ)/[S/sqrt(n)]

From given data, we have

µ = 60

Xbar = 65

S = 12

n = 64

t = (Xbar - µ)/[S/sqrt(n)]

t = (65 – 60)/[12/sqrt(64)]

t = 3.33

Answer: d. 3.33

Question 2

We are given

n = 64

df = n – 1 = 63

α = 0.01

Critical value = 2.3870

(by using t-table or excel)

Test statistic is greater than critical value.

So, we reject the null hypothesis

There is sufficient evidence to conclude that the mean transaction time is greater than 60 seconds.

a. a correct decision has been made