Question

Suppose that a company claims that its air fresheners last 23 days, on average. You take many large samples, and find, each time, that the mean number of days of the sample is outside the 95% confidence interval. Based on this information alone, which of the following is probably not the mean number of days that the company's air fresheners last?
A. 19
B. 21
C. 17
D. 23

Answer 1

Answer:

23

Step-by-step explanation:

Answer 2

Answer:

Option D is the answer.

Explanation:

A company claims that its air fresheners last 23 days, on average. Many large samples are taken each time it is found that the mean number of days of the sample is outside the 95% confidence interval.

This implies:

$23\times0.95=21.85$

So, below 21.85 is the probable mean number of days that the company's air fresheners last.

Therefore, 23 is not the mean number of days that the company's air fresheners last.