Question

23. A popular brand of AAA batteries has an effective use time of 12.3 hours, on average. A startup company claims that their AAA batteries last longer. The startup company tested 24,000 of their new batteries and computed a mean effective use time of 12.32 hours. Although the difference is quite small (72 seconds—or just over a minute), the effect was statistically significant (P-value < 0.0001).

It is appropriate to conclude which of the following?

A) The startup company has strong evidence that their AAA batteries last longer, on average.
B) The startup company has moderate evidence that their AAA batteries last longer, on average.
C) The startup company has proved that their AAA batteries last longer, on average.
D) None of the answer choices are correct. With such a large sample size, statistically significant results may not be of any practical importance.

Answer 1

Explanation:

We would set up the hypothesis test. This is a test of a single population mean since we are dealing with mean

For the null hypothesis,

µ = 12.3

For the alternative hypothesis,

µ > 12.3

This is a right tailed test.

The decision rule is to accept the null hypothesis if the significance level is lesser than the p value and reject the null hypothesis if the significance level is greater than the p value.

Let us assume a significance level of 0.05.

Since alpha, 0.05 > than the p 0.0001, then we would reject the null hypothesis.

The correct option would be

A) The startup company has strong evidence that their AAA batteries last longer, on average.

Answer 2

Option B

Explanation:

Although the difference is quite small (72 seconds—or just over a minute), the effect was statistically significant (P-value < 0.0001).

Since the P-value was less than 0.0001, the null hypothesis in this case can be rejected (H₀: ∪=12.3), concluding that the startup company has moderate/enough evidence that their AAA batteries last longer, on average.