Free Maths Calculator

Estimated Mean Calculator

Grouped data hides the individual values, so the mean can only be estimated. The middle of each class interval stands in for every value inside it, that midpoint is multiplied by the frequency, and the totals are divided. The word estimated is the whole point, and exams award marks for saying it.

Try It: Enter Your Numbers

Your question

Updates as you type

Answer

Method, Step by Step

    Worked Example

    Estimate the mean when 3 people scored 0 to 10, 7 scored 10 to 20, 6 scored 20 to 30 and 4 scored 30 to 40.

    1. Midpoints of the classes: 5, 15, 25 and 35
    2. Build the fx column:5×3 = 15, 15×7 = 105, 25×6 = 150, 35×4 = 140
    3. Totals:Σf = 20 and Σfx = 410
    4. Divide:410 ÷ 20 = 20.5

    Answer: 20.5

    Try These Yourself

    What is the midpoint of the class 20 to 30?Show answerHide answer

    Answer: 25

    (20 + 30) ÷ 2.

    Σfx is 410 and Σf is 20. What is the estimated mean?Show answerHide answer

    Answer: 20.5

    410 ÷ 20.

    Why is the answer only an estimate?Show answerHide answer

    Answer: The real values are unknown

    Every value is assumed to sit at the midpoint of its class.