SOLUTION: The reading speed of sixth-grade students is approximately normally distributed with a mean speed of 125 words per minute and a standard deviation of 24 words per minute. A school

Algebra ->  Probability-and-statistics -> SOLUTION: The reading speed of sixth-grade students is approximately normally distributed with a mean speed of 125 words per minute and a standard deviation of 24 words per minute. A school       Log On


   

Question 998593: The reading speed of sixth-grade students is approximately normally distributed with a mean speed of 125 words per minute and a standard deviation of 24 words per minute. A school psychiatrist wants to determine reading rates for "unusual" students (both slow and fast). Determine the reading rates of the middle 95% of all sixth-grade students. What are the cutoff points for the "unusual" readers (the outer 5%)?
Answer by fractalier(6550) About Me  (Show Source):
You can put this solution on YOUR website!
Plus or minus two sigmas will encompass 95% of a normal distribution.
Two sigmas is 48 words per minute.
Slow readers will be below 125-48 = 77 wpm.
Fast readers will be above 125+48 = 173 wpm.
The range for the 95% of readers is 77-173 wpm.