What is the mean and variance of the sample proportion of customers making a purchase? What is the probability that the sample proportion is less than 0.20? She calculated the probability that the sample proportion is lower than a propor- tion a, and the probability turned out 0.05. Then what is this number a?

A First Course in Probability (10th Edition)
10th Edition
ISBN:9780134753119
Author:Sheldon Ross
Publisher:Sheldon Ross
Chapter1: Combinatorial Analysis
Section: Chapter Questions
Problem 1.1P: a. How many different 7-place license plates are possible if the first 2 places are for letters and...
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A record store owner knows that 25% of customers entering her store make a purchase.
Consider a random sample consisting of 100 customers who entered the store.
(a) What is the mean and variance of the sample proportion of customers making a
purchase?
(b) What is the probability that the sample proportion is less than 0.20?
(c) She calculated the probability that the sample proportion is lower than a propor-
tion a, and the probability turned out 0.05. Then what is this number a?
Transcribed Image Text:A record store owner knows that 25% of customers entering her store make a purchase. Consider a random sample consisting of 100 customers who entered the store. (a) What is the mean and variance of the sample proportion of customers making a purchase? (b) What is the probability that the sample proportion is less than 0.20? (c) She calculated the probability that the sample proportion is lower than a propor- tion a, and the probability turned out 0.05. Then what is this number a?
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