If we were to construct a 95% confidence interval for the difference between the mean operating times of cordless toothbrushes manufactured by Company A and Company B, we would expect
A) the upper and lower limits to both be negative
B) the upper and lower limits to both be positive
C) that zero is not included in the interval
D) that zero is included in the interval
E) the upper and lower limits to both to be positive and that zero is not included in the interval

Question

Quizplus · Accepted Answer

A 95% confidence interval that includes zero suggests that there is no statistically significant difference between the mean operating times of the two companies' toothbrushes.

If We Were to Construct a 95% Confidence Interval for the Difference