How to Find Standard Deviation Using Range Rule of Thumb - Tutorial

How to Find Standard Deviation Using Range Rule of Thumb - Definition, Formula, Example

Definition:

Range is the simplest measure of variation, and it is the difference between high and low values. Standard deviation is the standard measure of variation.

Formula

s ≈ R / 4 R = Maximum - Minimum

Where,

s = Standard Deviation R = Range

Example :

Raju's half yearly exam marks are 85,89,92,80,95. Calcualte the standard deviation of the given marks using range rule of thumb.

Given

Data = {85,89,92,80,95} Minimum Mark = 80 Maximum Mark = 95

To Find,

Standard Deviation

Solution

Step 1

First, let us calculate the range value

Range (R) = Maximum - Minimum
= 95 - 80
R = 15
Step 2

Calculate the Standard Deviation

Standard Deviation (s) ≈ R/4
≈ 15 / 4
s ≈ 3.75

Result

Raju's approximate standard deviation is 3.75

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