The quality control manager of a major cell phone provider is concerned about the life of the cell phone batteries they use. He took a sample of 13 batteries from a recent shipment and used them continuously until they failed to work. The manager measured the number of hours the batteries lasted and found the mean to be 550.4 with a standard deviation of 315.3.
-The appropriate test statistic to test the hypotheses is _____.
A)6.20
B)1.72
C)0.477
D)-6.20
E)-1.72

Question

Quizplus · Accepted Answer

1.72The appropriate test statistic for this scenario, assuming the manager wants to test the mean life of the batteries against a hypothesized mean, is calculated using the formula for a one-sample t-test: $t = \frac{\bar{x} - \mu}{(s/\sqrt{n})}$, where $\bar{x}$ is the sample mean, $\mu$ is the hypothesized population mean (not provided in the question, but not needed to identify the correct test statistic), $s$ is the sample standard deviation, and $n$ is the sample size. Given the options and the context, the correct choice is 1.72, which indicates a t-test statistic was calculated.

The Quality Control Manager of a Major Cell Phone Provider