Question

the wechsler intelligence scale for children (wisc) are normally distributed with a mean of 100 and a standard deviation of 13. a. what is the probability that a randomly selected child has wisc score above 125? express your answer in decimals.

Answer 1

0.0274

Explanation:

A z-score measures exactly how many standard deviations above or below the mean a data point is.

The z-score for a normal distribution is given by the formula

`z = (X - \mu)/(\sigma)\\where\\\\X = data \;point}\\\mu = mean\\\sigma = standard\; deviation`

Plugging in values:
X = 125
μ = 100
σ = 13

z = (125-100)/13 = 1.92308

We are asked to find the probability that the score exceeds 125

This is the same as P(z > 1.92308) which is the area to the right of z = 1.92308

P(z > 1.92308) = 0.0274 (from either the tables or calculator)