Question 1170927: A variable is normally distributed with mean 20 and standard deviation 6. Use your graphing calculator to find each of the following areas. Write your answers in decimal form. Round to the nearest thousandth as needed.
a) Find the area to the left of 21.
b) Find the area to the left of 15.
c) Find the area to the right of 16.
d) Find the area to the right of 27.
e) Find the area between 15 and 29.
Answer by Boreal(15235)   (Show Source):
You can put this solution on YOUR website! z=(x-mean)/sd
z < (21-20)/6 or < 1/6. That probability is 0.5662 from 2ndVARS2 normalcdf (-6, (1/6))ENTER. Any number less than -6 may be used, I just picked that, since it is enough.
do the others the same way.
You may for the last do it two ways: Area to the left of 29 minus area to the left of 15.
The calculator would be 2nd VARS2normalcdf (15,29,20,6) ENTER
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To the right of 27 (z > (27-21)/6 or z > 1. This has area 0.1587.
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