What this calculator does
Mean & standard deviation from grouped data works out estimates the mean and standard deviation of a frequency table using class midpoints. Enter your own figures above and the answer updates as you type: nothing is fixed in the code, so the result reflects exactly the numbers you supply.
The formula this calculator evaluates is printed under the tool and explained below, so you can check the working by hand or reuse it in a spreadsheet.
The formula
Formulax̄ = Σ(fᵢmᵢ)/Σfᵢ; s = √[Σfᵢ(mᵢ−x̄)² / (Σfᵢ−1)], using midpoint mᵢ of each class
The inputs explained
| Field | What to enter |
|---|---|
| Class midpoints (comma separated) | A list of numbers, separated by commas or spaces. |
| Frequencies (comma separated) | A list of numbers, separated by commas or spaces. |