According to The World Bank, only 9% of the population of Uganda had access to electricity as of 2009. Suppose we randomly sample 150 people in Uganda. Let X = the number of people who have access to electricity.

a. What is the probability distribution for X?

b. Using the formulas, calculate the mean and standard deviation of X.

c. Use your calculator to find the probability that 15 people in the sample have access to electricity.

d. Find the probability that at most ten people in the sample have access to electricity.

e. Find the probability that more than 25 people in the sample have access to electricity

Short Answer

Expert verified

a. The probability distribution of X is 0.09

b. The mean is 13.5and standard deviation is 3.5

c. The probability that 15people in the sample have access to electricity is0.0988

d. The probability that at most ten people in the sample have access to electricity is 0.1987

e. The probability that more than 25 people in the sample have access to electricity is0.9991

Step by step solution

01

Content Introduction

The binomial distribution determines the probability of looking at a specific quantity of a hit results in a specific quantity of trials

02

Explanation (part a)

We are given,

9%of the population of Uganda had access to electricity as of 2009 and we randomly chose a sample of 150 people in Uganda. So. here nis the sample size and pis the probability.

Therefore,

The probability distribution of X isp=0.09

03

Explanation (part b)

We are given:n=150,p=0.09

The mean is:

μ=np, where

n=numberofsamplesp=probabilityofsamples

Therefore, the mean is

role="math" localid="1649250625500" μ=npμ=150×0.09μ=13.5

Standard deviation is:

σ=np(1-p)σ=150×0.09(1-0.09)σ=3.5

04

Explanation (part c)

Using binompdf:

the probability that 15people in the sample have access to electricity is:

role="math" localid="1649250800761" binompdf(150,0.09,15)=150!15!(150-15)!0.0915(1-0.09)50-15binompdf(150,0.09,15)=150!15!(150-15)!0.0915(1-0.09)35binompdf(150,0.09,15)=0.0988

05

Explanation (part d) 

The probability that at most ten people in the sample have access to electricity is:

binompdf(150,0.09,10)=k=010150!!(k150-k)!0.09k(1-0.09)50-kbinompdf(150,0.09,10)=0.1897

06

Explanation (part e)

The probability that more than 25 people in the sample have access to electricity is:

binompdf(150,0.09,25)=k=025150!!(k150-k)!0.09k(1-0.09)50-kbinompdf(150,0.09,25)=0.9991

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