A loan officer compares the interest rates for 48-month fixed-rate auto loans and 48-month variable-rate auto loans. Two independent, random samples of auto loan rates are selected. A sample of five 48-month variable-rate auto loans had the following loan rates:

2.40%

3.01%

2.882%

3.23%

3.23%

while a sample of five 48-month fixed-rate auto loans had loan rates as follows:

4.040%

3.78%

4.375%

3.71%

4.21%

Figure 11.7

JMP Output of Testing the Equality of Mean Loan Rates for Variable and Fixed 48-Month Auto Loans
Means and Std Deviations
Level	Number	Mean	Std Dev
Fixed	5	4.02300	0.341878
Variable	5	2.95040	0.281149
t Test
Variable-Fixed
Assuming equal variances
Difference	1.0726	t Ratio	5.41847
Std Err Dif	0.1980	DF	8
Upper CL Dif	0.6161	Prob > |t|	0.0006*
Lower CL Dif	1.5291	Prob > t	0.9997
Confidence	0.95	Prob < t	<0.0003*

(d) Calculate a 95 percent confidence interval for the difference between the mean rates for fixed- and variable-rate 48-month auto loans. Can we be 95 percent confident that the difference between these means exceeds .4 percent? (Round your answers to 4 decimal places.)

Confidence interval =[,]?

(e) Use a hypothesis test to establish that the difference between the mean rates for fixed- and variable-rate 48-month auto loans exceeds .4 percent. Use equal to .05. (Round your t answer to 4 decimal places and other answers to 1 decimal place.)

T-Value = ?