01
Press these keys
2nd→VARS→DISTR→normalcdf(
Step 1 of 4. Press 2nd.
02
Walkthrough
- 1Translate
Write the event, for example P(a<X<b), before touching the calculator.
- 2Enter bounds
normalcdf(lower,upper,μ,σ). For a distant tail use −1E99 or 1E99 only as a calculator approximation to infinity.
- 3Check scale
The probability must lie from 0 to 1 and match a sketch of the area.
03
Worked example
X~N(50,8²). Find P(42<X<60).
NORMAL FLOAT AUTO REAL MP
normalcdf(42,60,50,8).735...AnswerP(42<X<60)≈0.735.