A company that produces computers recently tested the battery in its latest laptop in six separate trials.The battery lasted 8.23,7.89,8.14,8.25,8.30,and 7.95 hours before burning out in each of the tests.Assuming the battery duration is normally distributed,construct a 95% confidence interval for the mean battery life in the new model.
A) [7.9489,8.3045]
B) [7.9575,8.2959]
C) [7.9873,8.2661]
D) [7.9912,8.2622]

Question

Quizplus · Accepted Answer

The correct answer is A because the confidence interval is calculated as (sample mean +/- margin of error), where the margin of error is (t-value * standard error of the mean). The t-value for a 95% confidence interval with 5 degrees of freedom is 2.571, and the standard error of the mean is 0.152. Therefore, the confidence interval is (8.12 +/- 0.38) = [7.9489, 8.3045].

A Company That Produces Computers Recently Tested the Battery in Its