Please explain in the problem below how a) λ was obtained and b) what went wrong with the Poisson approximation.
Please explain in the problem below how a) λ was obtained and b) what went wrong with the Poisson approximation.
A First Course in Probability (10th Edition)
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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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Question
Please explain in the problem below how a) λ was obtained and b) what went wrong with the Poisson approximation.
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![Example 5.8. It is known that of 313.6 million of US population, about 200 million have high-speed
Internet access at home. Thus the population proportion of high-speed Internet users is 0.6378. Suppose
1500 people are randomly selected. What is the probability that at least 1000 of those responding to the
survey have high-speed Internet access?
Solution. We interpret 0.6378 proportion as p and a sample of 1500 people selected for the survey as a
sample of 1500 independent Bernoulli trials, so that X = X₁ + ... + X1500 € [B(1500, 0.6378)] gives
the number of those in the surveyed sample who have high-speed Internet access. Thus, we are
interested to find](/v2/_next/image?url=https%3A%2F%2Fcontent.bartleby.com%2Fqna-images%2Fquestion%2Fdb82eee3-c597-43b7-b98f-cffc18fbca72%2Fb60cbaf6-f958-409c-8c9d-6c3286d2d8ac%2F1tl9e96m_processed.png&w=3840&q=75)
Transcribed Image Text:Example 5.8. It is known that of 313.6 million of US population, about 200 million have high-speed
Internet access at home. Thus the population proportion of high-speed Internet users is 0.6378. Suppose
1500 people are randomly selected. What is the probability that at least 1000 of those responding to the
survey have high-speed Internet access?
Solution. We interpret 0.6378 proportion as p and a sample of 1500 people selected for the survey as a
sample of 1500 independent Bernoulli trials, so that X = X₁ + ... + X1500 € [B(1500, 0.6378)] gives
the number of those in the surveyed sample who have high-speed Internet access. Thus, we are
interested to find
![1200) 0.6378 0.36221500-k
Now the above is a computational challenge. The normal approximation, due to the Central Limit
Theorem (to be explored in Chapter V, section 2), would be a remedy. Alternatively, we can use R
language to compute the above probability precisely. The procedure will be as follows.
P{X > 1000} = 1− P{X < 1000} = 1 − P{X ≤ 999}
P{X ≥ 1000} = 150
implying
k=1000
> 1-pbinom (999,1500,.6378)
[1] 0.01042895
which reads
P{X > 1000} = 0.01042895.
Here pbinom (999,1500,.6378) calculates
999
Σ (¹500) 0.6378* 0.3622¹500-k
Now if we use the Poisson approximation with λ = 956.7 (why?) we arrive at
> 1-ppois(999,956.7)
[1] 0.08395288
The result significantly differs from that of direct binomial. The student needs to explain the
discrepancy. (See Problem 5.6.)](/v2/_next/image?url=https%3A%2F%2Fcontent.bartleby.com%2Fqna-images%2Fquestion%2Fdb82eee3-c597-43b7-b98f-cffc18fbca72%2Fb60cbaf6-f958-409c-8c9d-6c3286d2d8ac%2Fcnzeca_processed.png&w=3840&q=75)
Transcribed Image Text:1200) 0.6378 0.36221500-k
Now the above is a computational challenge. The normal approximation, due to the Central Limit
Theorem (to be explored in Chapter V, section 2), would be a remedy. Alternatively, we can use R
language to compute the above probability precisely. The procedure will be as follows.
P{X > 1000} = 1− P{X < 1000} = 1 − P{X ≤ 999}
P{X ≥ 1000} = 150
implying
k=1000
> 1-pbinom (999,1500,.6378)
[1] 0.01042895
which reads
P{X > 1000} = 0.01042895.
Here pbinom (999,1500,.6378) calculates
999
Σ (¹500) 0.6378* 0.3622¹500-k
Now if we use the Poisson approximation with λ = 956.7 (why?) we arrive at
> 1-ppois(999,956.7)
[1] 0.08395288
The result significantly differs from that of direct binomial. The student needs to explain the
discrepancy. (See Problem 5.6.)
Expert Solution
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Step 1
Given
The population proportion of high speed internet users
Sample size
Step by step
Solved in 2 steps
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