Consider the following hypothesis test:
\( \mathrm{H_0}:\mu\le 25 \)
\( \mathrm{H_a}:\mu\gt 25 \)
A sample of 25 provided a sample mean of 27.80. The population standard deviation is 5, then the value of the test statistic is
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → 2.8
The population standard deviation is known, so the test statistic is
\( \displaystyle z=\frac{\bar{x}-\mu_0}{\sigma/\sqrt{n}} \)
\( \displaystyle =\frac{27.8-25}{5/\sqrt{25}} \)
\( \displaystyle =\frac{2.8}{1}=2.8 \)