Standard x-ray machines should give radiation dosages below 5.00 mill roentgens (mil-r). To test a certain x-ray machine, a sample of 36 observations is taken with a mean of 4.13 mil-r and a standard deviation of 1.91 mil-r.
-The appropriate test statistic to test the hypotheses is _____.
A)-2.73
B)-3.78
C)-0.455
D)3.78
E)2.73

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 standard deviation, and $n$ is the sample size. Plugging in the given values: $z = \frac{4.13 - 5.00}{(1.91/\sqrt{36})} = -2.73$.

Standard X-Ray Machines Should Give Radiation Dosages Below 5