Question

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Answer 1

Calculate the z-score of 140 using
\(\mu=100\), \(\sigma=15\), x=140, and
z=\((x-\mu)/\sigma\)=3.666667
Then look up a normal distribution table (or use your calculator) to find the area of left tail of Z=+3.666667. This area is the proportion of the population having equal or less IQ as the statistician.