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A quality control inspector has drawn a sample of 1616 light bulbs from a recent production lot. Suppose 30%30% of the bulbs in the lot are defective. What is the probability that exactly 44 bulbs from the sample are defective? Round your answer to four decimal places.

User Xu
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Answer:

0.2040 = 20.40% probability that exactly 4 bulbs from the sample are defective.

Explanation:

For each bulb, there are only two possible outcomes. Either it is defective, or it is not. The probability of a bulb being defective is independent from other bulbs, so we use the binomial probability distribution to solve this question.

Binomial probability distribution

The binomial probability is the probability of exactly x successes on n repeated trials, and X can only have two outcomes.


P(X = x) = C_(n,x).p^(x).(1-p)^(n-x)[\tex]</p><p>In which [tex]C_(n,x)[\tex] is the number of different combinations of x objects from a set of n elements, given by the following formula.</p><p>[tex]C_(n,x) = (n!)/(x!(n-x)!)[\tex]</p><p>And p is the probability of X happening.</p><p><strong>Suppose 30% of the bulbs in the lot are defective.</strong></p><p>This means that [tex]p = 0.3

A quality control inspector has drawn a sample of 16 light bulbs from a recent production lot.

This means that
n = 16

What is the probability that exactly 4 bulbs from the sample are defective?

This is P(X = 4).

[tex]P(X = x) = C_{n,x}.p^{x}.(1-p)^{n-x}[\tex]

[tex]P(X = 4) = C_{16,4}.(0.3)^{4}.(0.7)^{12} = 0.2040[\tex]

0.2040 = 20.40% probability that exactly 4 bulbs from the sample are defective.

User Netsurfer
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