Scores of adults aged 60 to 64 on a common IQ test are approximately Normally distributed with mean 90 and standard deviation 15.
Since IQ scores of adults aged 60 to 64 are Normally distributed with mean 90 and standard deviation 15, then about 40% of the scores are between
A) 60 and 120.
B) 45 and 135.
C) 85 and 90.
D) the 25th and 75th percentiles.
E) the 30th and 70th percentiles.

Question

Quizplus · Accepted Answer

The 30th and 70th percentiles capture the middle 40% of a normal distribution.

Scores of Adults Aged 60 to 64 on a Common