Eight persons enter a supermarket. From past experience, it is known that 25% of the people entering the supermarket make a purchase. Let X be the number of customers who will make a purchase. 1. What are the possible values of the random variable X? 2. Construct the probability distribution of X. P(X=x) 3. What is the probability that a) at least four persons will make a purchase?

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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Note: Answer only 1, 2, 3(a)

Eight persons enter a supermarket. From past experience, it is known that 25% of the people entering the supermarket
make a purchase.
Let X be the number of customers who will make a purchase.
1. What are the possible values of the random variable X?
2. Construct the probability distribution of X.
P(X=x)
3. What is the probability that
a) at least four persons will make a purchase?
b) two or three persons will make a purchase?
c) at most two persons will make a purchase?
4. Out of the eight persons entering a supermarket, how many are expected to make a purchase?
5. Compute the standard deviation of the random variable X.
Transcribed Image Text:Eight persons enter a supermarket. From past experience, it is known that 25% of the people entering the supermarket make a purchase. Let X be the number of customers who will make a purchase. 1. What are the possible values of the random variable X? 2. Construct the probability distribution of X. P(X=x) 3. What is the probability that a) at least four persons will make a purchase? b) two or three persons will make a purchase? c) at most two persons will make a purchase? 4. Out of the eight persons entering a supermarket, how many are expected to make a purchase? 5. Compute the standard deviation of the random variable X.
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