SOLUTION: On the assumption that IQ'S are normally distributed in the population with a mean of 100 and a standard deviation of 15. Find the proportion of people with IQ'S between 85-120

Algebra ->  Permutations -> SOLUTION: On the assumption that IQ'S are normally distributed in the population with a mean of 100 and a standard deviation of 15. Find the proportion of people with IQ'S between 85-120      Log On


   

Question 1161884: On the assumption that IQ'S are normally distributed in the population with a mean of 100 and a standard deviation of 15. Find the proportion of people with IQ'S between 85-120
Answer by Boreal(15235) About Me  (Show Source):
You can put this solution on YOUR website!
z=(x-mean)/sd
so want z between -1 and +1.33
and that is 0.7501 probability
Alternatively, use 2nd VARS 2 normalcdf(85,120,100,15) ENTER in that order, and it does the whole calculation at once and does it exactly, whereas the above 1.333 is not quite (4/3).