Core3 min

Standardize and check z-scores

You need to compare a value with a normal mean and standard deviation.

01

Press these keys

(x−μ)÷σ

Step 1 of 7. Press (.

02

Walkthrough

  1. 1
    Write formula

    z=(x−μ)/σ.

  2. 2
    Use brackets

    Enter (x−μ)÷σ so the entire difference is divided.

  3. 3
    Interpret sign

    Positive z is above the mean; negative z is below; |z| counts standard deviations.

03

Worked example

For μ=50, σ=8, standardize x=60.

Answerz=1.25.