8
QuizMultiple Choice
Testing a Claim about a Difference between Proportions
Question 8 • AQR_A_IC
The owner of a computer company claims that the proportion of defective computer chips produced at plant A is higher than the proportion of defective chips produced by plant B. A quality control specialist takes a random sample of 80 chips from production at plant A and determines that there are 12 defective chips. The specialist then takes a random sample of 90 chips from production at plant B and determines that there are 10 defective chips. Let pA = the true proportion of defective chips from plant A and pB = the true proportion of defective chips from plant B. Which of the following is the correct standardized test statistic for the hypotheses, ?
Answer
A
z = StartStartFraction 0.12 minus 0.10 OverOver StartRoot StartFraction (12) (68) Over 80 EndFraction + StartFraction (10) (0.80) Over 90 EndFraction EndRoot EndEndFraction
B
z = StartStartFraction 0.10 minus 0.12 OverOver StartRoot StartFraction (0.15) (0.85) Over 80 EndFraction + StartFraction (0.11) (0.89) Over 90 EndFraction EndRoot EndEndFraction
C
z = StartStartFraction 0.12 minus 0.10 OverOver StartRoot StartFraction (0.13) (0.87) Over 80 EndFraction + StartFraction (0.13) (0.87) Over 90 EndFraction EndRoot EndEndFraction
D
z = StartStartFraction 0.10 minus 0.12 OverOver StartRoot StartFraction (0.13) (0.87) Over 80 EndFraction + StartFraction (0.13) (0.87) Over 90 EndFraction EndRoot EndEndFraction