Question Details

A machine produces a defective component with a probability of 0.015. The number of defective components in a packed box containing 200 components produced by the machine follows a Poisson distribution. The mean and the variance of the distribution are

Options

A

3 and 3, respectively

B

√3 and √3 , respectively

C

0.015 and 0.015, respectively

D

3 and 9, respectively

Correct Answer :

3 and 3, respectively

Solution :

The correct option is 3 and 3, respectively.

Step-by-step Explanation:

Based on the problem description and as verified from the formulas shown in the attached image, we can define the parameters of the distribution as follows:
1. The probability of producing a defective component, represented by
P=0.015
2. The number of components in a packed box, represented by
n=200

For a Poisson distribution that approximates a binomial distribution with a large number of trials n and a small probability P, the mean (represented by λ) is calculated as:

mean=λ=n×P
Substituting the given values:
λ=200×0.015=3

One of the key defining properties of the Poisson distribution is that its mean and variance are equal. Thus, we have:

variance=σ2=λ=3

Consequently, both the mean and the variance of the distribution are 3. This matches the calculation steps shown in the image:
mean=λ=np=200×0.015=3
and
variance=σ2=λ=3.

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