A marketing researcher for a phone company surveys 300 people and finds that the

Question

A marketing researcher for a phone company surveys 300 people and finds that the proportion of clients who are likely to switch providers when their contract expires is 0.15. a) What is the estimated standard deviation of the sampling distribution of the proportion? b) If she wants to reduce the estimated standard deviation by half, how large of a sample would she need? a) The estimated standard deviation of the sampling distribution of the proportion is. (Round to four decimal places as needed.) b) She will need a sample of (Type a whole number.)

Explanation / Answer

Given:

p=.15
n=300

a. Estimated standard deviation = sqrt(npq) = sqrt(.15*300*.85) = 6.185
b. If we want to reduce stdev by 1/2 times the sample should be 300/2^2 times = 75

So, sample size should be 75 to reduce the stdev by 1/2

Related Questions

Navigate

• Browse (All)
• Browse A
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.