Question

A manufacturer of carpentry screws claims that its production machine is very accurate and that the standard deviation of the length of all screws produced is .08 mm or less. A sample of 30 screws showed a standard deviation of .10. The test statistic to test the manufacturer's claim is _____.
a. 45.31
b. 23.2
c. 18.56
d. 19.2

Answer 1

Answer:

Option A) 45.31

Step-by-step explanation:

We are given the following information in the question:

Population standard deviation, σ = 0.08

$\sigma^2 = (0.08)^2 = 0.0064$

Sample size, n = 30

Sample standard deviation, s = 0.10

$s^2 = (0.10)^2 = 0.01$

Test statistic =

$\displaystyle\frac{(n-1)s^2}{\sigma^2} = \frac{(30-1)(0.01)}{(0.0064)} = 45.31$

Option A) 45.31