Casio fx-9860GII - Page 55

Using a graphic display calculator
© Oxford University Press 2012: this may be reproduced for class use solely for the purchaser’s institute
Casio fx-9860GII
Press
F5
DIST
F1
NORM
F3
InvN to use the Inverse Normal function.
Press
F2
Var.
Enter Tail as Right (
F2
), Area as 0.2, σ as 12 and μ as 75.
Press
EXE
.
So if P ( X > x) = 0.2 then x = 85.1 (to 3 sf).
This sketch of a normal distribution curve
shows the value of x and the probabilities
for Example 59.
x
0.8 0.2
85.1
You should enter
the values: Area
(probability),
σ and μ ,
in order.
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