Question 525398: I am having a hard time understanding standard normal distribution:
how would you figure this from a problem such as:
P(1.22 < Z < 2.15)
Found 2 solutions by richard1234, Edwin McCravy:
Answer by richard1234(7193)   (Show Source):
You can put this solution on YOUR website! That question is asking, for a normal curve with  and  , what is the probability that the z-score is between 1.22 and 2.15. Use your calculator and the normal cdf (cumulative distribution function) to evaluate it. On a TI calculator, it might look something like
normcdf(1.22, 2.15, 0, 1)
The syntax might be slightly different on other calculators.
Answer by Edwin McCravy(20055)  (Show Source):
You can put this solution on YOUR website!
You want to know what decimal fraction the green area
is of the whole area on the normal curve.
Notice it starts at z=1.22 on the z-axis and goes to z=2.15.
On a TI-83 or 84 calculator you can find it by
normalcdf(1.22,2.15). You get .0954549502
On a normal table you look up
z = 2.15 and find either .4842 or .9842, depending on what
kind of z-table you have.
Then you look up
z = 1.22 and find either .3888 or .8888, depending on what
kind of z-table you have.
Then you subtract the two values
.4842-.3888 or .9842-.8888
and you'll get .0954
That's the fraction of the total area which the green
area is of the entire area. As a percent the green area
is 9.54% of the total area between the z-axis and the normal
curve.
Edwin
Edwin
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