A machinist makes engine parts with an axle diameter of 0.6 inch. A random sample of 17 parts shows the mean diameter of 0.64 inch with a standard deviation of 0.04 inch. The t-test statistic is :
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → 4
Here μ = 0.6, n = 17, \( \bar{x}=0.64 \) and s = 0.04. The standard deviation of the sample is taken with divisor n, so the one-sample t statistic uses \( \sqrt{n-1} \):
\( \displaystyle t=\frac{\bar{x}-\mu}{s/\sqrt{n-1}} \)
\( \displaystyle t=\frac{0.64-0.6}{0.04/\sqrt{16}} \)
\( \displaystyle =\frac{0.04}{0.01} \)
\( \displaystyle =4 \)