Question

In: Statistics and Probability

Assume that IQ scores are normally distributed with a mean of 100 and standard deviation of...

Assume that IQ scores are normally distributed with a mean of 100 and standard deviation of 12. Find the probability that: (a) a randomly selected person has an IQ score less than 92. (b) a randomly selected person has an IQ score greater than 108.

Solutions

Expert Solution

We are given :

Let X denote the IQ score of a person.

(a)

Probability that  a randomly selected person has an IQ score less than 92 = P(X<92)

We use Excel function " NORMSDIST()" to find the above probability as :

Hence,

Probability that  a randomly selected person has an IQ score less than 92 = 0.2525

(b)

Probability that  a randomly selected person has an IQ score greater than 108 = P(X>108)

We use Excel function " NORMSDIST()" to find the above probability as :

Hence,

Probability that  a randomly selected person has an IQ score greater than 108 = 0.2525


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