IQ is normally distributed with a mean of 100 and a standard deviation of 15. Suppose one individual is randomly chosen. Let X = IQ of an individual.Find the probability that the person has an IQ score between 92 and 108.

Respuesta :

Using the normal distribution, it is found that there is a 0.4038 = 40.38% probability that the person has an IQ score between 92 and 108.

Normal Probability Distribution

The z-score of a measure X of a normally distributed variable with mean [tex]\mu[/tex] and standard deviation [tex]\sigma[/tex] is given by:

[tex]Z = \frac{X - \mu}{\sigma}[/tex]

  • The z-score measures how many standard deviations the measure is above or below the mean.
  • Looking at the z-score table, the p-value associated with this z-score is found, which is the percentile of X.

The mean and the standard deviation are given, respectively, by:

[tex]\mu = 100, \sigma = 15[/tex].

The probability that the person has an IQ score between 92 and 108 is the p-value of Z when X = 108 subtracted by the p-value of Z when X = 92, hence:

X = 108:

[tex]Z = \frac{X - \mu}{\sigma}[/tex]

[tex]Z = \frac{108 - 100}{15}[/tex]

Z = 0.53

Z = 0.53 has a p-value of 0.7019.

X = 92:

[tex]Z = \frac{X - \mu}{\sigma}[/tex]

[tex]Z = \frac{92 - 100}{15}[/tex]

Z = -0.53

Z = -0.53 has a p-value of 0.2981.

0.7019 - 0.2981 = 0.4038.

0.4038 = 40.38% probability that the person has an IQ score between 92 and 108.

More can be learned about the normal distribution at https://brainly.com/question/4079902

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