A problem with a phone line that prevents a customer

from receiving or making calls is upsetting to both the customer

and the telecommunications company. The file Phone

contains samples of 20 problems reported to two different

offices of a telecommunications company and the time to

clear these problems (in minutes) from the customers' lines:

Central Office I Time to Clear Problems (minutes)

1.48 1.75 0.78 2.85 0.52 1.60 4.15 3.97 1.48 3.10

1.02 0.53 0.93 1.60 0.80 1.05 6.32 3.93 5.45 0.97

Central Office II Time to Clear Problems (minutes)

7.55 3.75 0.10 1.10 0.60 0.52 3.30 2.10 0.58 4.02

3.75 0.65 1.92 0.60 1.53 4.23 0.08 1.48 1.65 0.72

a. Assuming that the population variances from both offices

are equal, is there evidence of a difference in the mean

waiting time between the two offices? (Use a = 0.05.)

b. Find the p-value in (a) and interpret its meaning.

c. What other assumption is necessary in (a)?

d. Assuming that the population variances from both offices

are equal, construct and interpret a 95% confidence interval

estimate of the difference between the population

means in the two offices.

Time Location

1.48 1

1.75 1

0.78 1

2.85 1

0.52 1

1.60 1

4.15 1

3.97 1

1.48 1

3.10 1

1.02 1

0.53 1

0.93 1

1.60 1

0.80 1

1.05 1

6.32 1

3.93 1

5.45 1

0.97 1

7.55 2

3.75 2

0.10 2

1.10 2

0.60 2

0.52 2

3.30 2

2.10 2

0.58 2

4.02 2

3.75 2

0.65 2

1.92 2

0.60 2

1.53 2

4.23 2

0.08 2

1.48 2

1.65 2

0.72 2

I am having a difficult time understanding how to perform the calculation in excel. Can you please show me how to perform these calculations in excel?