An injector molder produces plastic pens. The process is designed to produce pens with a mean weight of 0.250 grams. To investigate whether the injection molder is operating satisfactorily, 40 pens were randomly sample with a mean of 0.2525g and a standard deviation of .0022g.
-The test statistic is _____.
A)7.187
B)337
C)3.371
D)-.337
E)-7.187

Question

Quizplus · Accepted Answer

The test statistic is calculated using the formula: $Z = \frac{\bar{x} - \mu}{(\sigma/\sqrt{n})}$, where $\bar{x}$ is the sample mean, $\mu$ is the population mean, $\sigma$ is the sample standard deviation, and $n$ is the sample size. Plugging in the given values: $Z = \frac{0.2525 - 0.250}{(0.0022/\sqrt{40})} = 7.187$.

An Injector Molder Produces Plastic Pens