Question

The quality manager believes there may be a relationship between the experience level of an inspector and whether a product passes or fails inspection. Inspection records were reviewed for 630 units of a particular product, and the number of units which passed and failed inspection was determined based on three inspector experience levels. The results are shown in the following table.

Decision	Experience Level
	Low (< 2 years)			Medium (2-8 years)			High (> 8 years)
Pass		153			285			105
Fail		18			47			23

a. Select the competing hypotheses to determine whether the inspector pass/fail decision depends on experience level.

• H₀: Inspector pass/fail decision and experience level are independent; H_A: Inspector pass/fail decision and experience level are dependent.

• H₀: Inspector pass/fail decision and experience level are dependent; H_A: Inspector pass/fail decision and experience level are independent.

b. Calculate the value of the test statistic. (Round the intermediate calculations to at least 4 decimal places and final answer to 3 decimal places.)

c. Find the p-value.

• 0.05 p-value < 0.10
• 0.025 p-value < 0.05
• p-value 0.10
• 0.01 p-value < 0.025

• p-value < 0.01

Answer 1

The statistical software output for this problem is:

Hence,

a) H₀: Inspector pass/fail decision and experience level are independent; H_A: Inspector pass/fail decision and experience level are dependent.

b) Test statistic = 3.405

c) p-value > 0.10