THE NEXT QUESTIONS ARE BASED ON THE FOLLOWING INFORMATION:
A restaurant manager was in charge of purchasing new microwaves for his restaurant.The choices were narrowed to two available models.Since the two models cost about the same,the manager was interested in determining whether there was a difference in the amount of power consumed when operated at high voltages.Based on two independent random samples,the following summary information was computed:

-Find a 90% confidence interval for the difference in the amount of power consumed at high voltages by the two models.
A)0.2 ± 0.49
B)0.2 ± 0.16
C)0.2 ± 0.05
D)0.2 ± 1.28

Question

THE NEXT QUESTIONS ARE BASED ON THE FOLLOWING INFORMATION:
A restaurant manager was in charge of purchasing new microwaves for his restaurant.The choices were narrowed to two available models.Since the two models cost about the same,the manager was interested in determining whether there was a difference in the amount of power consumed when operated at high voltages.Based on two independent random samples,the following summary information was computed:
 
-Find a 90% confidence interval for the difference in the amount of power consumed at high voltages by the two models.
A)0.2 ± 0.49 
B)0.2 ± 0.16 
C)0.2 ± 0.05 
D)0.2 ± 1.28

Quizplus · Accepted Answer

The 90% confidence interval for the difference in power consumption between two models, given as a point estimate (0.2) plus or minus a margin of error (0.49), correctly reflects the range within which the true difference is likely to fall with 90% confidence. The margin of error is determined by the standard error of the difference and the critical value for the desired confidence level, which in this case corresponds to the values given in option A.