Question

A quality control inspector is testing microprocessor chips made during a single day by a new machine to determine the proportion of defective chips. She selects an SRS of 80 chips from the 3000 chips produced by the machine on that day. it turns out that six of the chips are defective. Which of the following conditions for constructing a confidence interval for the proportion of defective chips has been violated?

A. np>10 and n(1-p) > 10
B. An SRS has been taken from the population of interest.
C. The population is at least 10 times the size of the sample.
D. The population is approximately Normally distributed.
E. There appear to be no violations.

Answer 1

The answer is "Choice A".

Explanation:

`\to \hat p = (6)/(80) = 0.075\\\\\to n \hat p = 6 \\geq 10`

In this question, "choice A" violates the population size at a minimum of ten times the magnitude including its sample, and therefore does not violate its requirement that is the sample, which was taken in change.