Calculating X-Values From Normal Probabilities - Casio fx-9860GII Instructions Manual

P(X < 190) = 0.401 (to 3 sf)
P(x > 194)
b
Press EXIT to return to the entry screen.
Enter Lower Bound as 194, Upper Bound as 1E99, σ as 20 and μ as 195.
P(X > 194) = 0.520 (to 3 sf)
c P(187 < x < 196)
EXIT
Press to return to the entry screen.
Enter Lower Bound as 187, Upper Bound as 196, μ as 195 and σ as 20.
P(187 < X < 196) = 0.175 (to 3 sf)

5.15 Calculating X-values from normal probabilities

In some problems you are given probabilities and have to calculate the associated
values of X. To do this, use the Inverse Normal function.
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When using the Inverse Normal function,
make sure you fi nd the probability on the
correct side of the normal curve. If the area is
the lower tail, that is it is in the form P(X < x),
use 'Left' tail.
If you are given the upper tail P(X > x), you
should use 'Right' tail.
Casio fx-9860GII
Using a graphic display calculator 53