Stereo speakers are manufactured with a probability of 0.100.10 being defective. TwentyTwenty speakers are randomly selected. Let the random variable X be defined as the number of defective speakers. Find the expected value and the standard deviation.

The expected value of X is 2 with a standard deviation of 1.34.

Step-by-step explanation:

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

Binomial probability distribution

Probability of exactly x sucesses on n repeated trials, with p probability.

The expected value of the binomial distribution is:

The standard deviation of the binomial distribution is:

Stereo speakers are manufactured with a probability of 0.1 of being defective

This means that

Twenty speakers are randomly selected.

This means that

Let the random variable X be defined as the number of defective speakers. Find the expected value and the standard deviation.

The expected value of X is 2 with a standard deviation of 1.34.

maximum area = xy = (16)(32) = 512 ft2

to maximize the area of the garden, the side of the fence parallel to the side of the house should be 32 ft long, and the other two sides should both have length 16 ft.'

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