SOLUTION: Test scores are normally distributed with a mean of 76 and a standard deviation of 10. a. In a group of 230 tests, how many students score above 96? b. In a group of 230 test

Algebra ->  Statistics  -> Density-curves-and-normal-distributions -> SOLUTION: Test scores are normally distributed with a mean of 76 and a standard deviation of 10. a. In a group of 230 tests, how many students score above 96? b. In a group of 230 test      Log On


   

Question 1159795: Test scores are normally distributed with a mean of 76 and a standard deviation of 10.
a. In a group of 230 tests, how many students score above 96?
b. In a group of 230 tests, how many students score below 66?
c. In a group of 230 tests, how many students score within one standard deviation of the mean?
Answer by Edwin McCravy(20064) About Me  (Show Source):
You can put this solution on YOUR website!
a. In a group of 230 tests, how many students score above 96? 


On your TI-84, 2ND VARS

normalcdf(96,1E99,76,10)  <-- the "E" to use is 2ND then the comma key

0.022759962

multiply by 230

5.232514263

Round down to 5 students.

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b. In a group of 230 tests, how many students score below 66? 

normalcdf(-1E99,66,76,10)

0.1586552596

multiply by 230

36.4907097

Round down to 36 students.

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c. In a group of 230 tests, how many students score within one standard deviation of the mean? 

That's between 76-10=66 and 76+10=86

normalcdf(66,86,76,10)

0.682689809

multiply by 230


157.0185806

Round down to 157 students.


Edwin