One of the leading dot-com companies has found that the proportion of customers who come into its Web site that actually makes a purchase is 0.045. The company plans to see whether this rate still holds by selecting a random sample of 200 hits on its Web site. Given that the 0.045 rate still applies, what is the standard deviation of the sampling distribution?
A) Approximately 0.0147
B) About 0.0002
C) About 0.0354
D) Can't be determined without knowing the mean.

Question

Quizplus · Accepted Answer

The standard deviation of the sampling distribution (σp) can be calculated using the formula for the standard deviation of a proportion: σp = sqrt[(p(1-p))/n], where p is the proportion (0.045 in this case) and n is the sample size (200). Plugging in the values: σp = sqrt[(0.045 * 0.955) / 200] ≈ 0.0147.

One of the Leading Dot-Com Companies Has Found That the Proportion