Assume that adults have IQ scores that are normally distributed with a mean of 100 and standard deviation of 15 (as on the Wechsler test). Find the probability that 1. a randoml…

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asked Apr 24, 2023 220k views

1 Answer

Kelvt · Answer 1 · 2023-04-29T10:15:15+0000

The Solution:

Given:

$\begin{gathered} X=120 \\ \mu=100 \\ \sigma=15 \end{gathered}$

We are required to find the probability that the adult selected has IQ greater than 120.

By the Z-statistic formula, we have:

$Z=(X-\mu)/(\sigma)=(120-100)/(15)=(20)/(15)=(4)/(3)=1.3333$

From the Z score tables, we have:

$P(Z>1.3333)=0.0912\approx0.091$

Therefore, the correct answer is 0.091