Calculation of Standard Devaition and Variance

Calculation of Standard Deviation for Discrete Series.

In the discrete series, when deviations are taken from actual mean, the formula is








Example:

From the following data, compute the value of standard deviations and variance





Suggested answer:
















Standard deviation from assumed mean method:



















=588/40-(52/40)^2
=14.7-1.69
=13.01



Step 1:

If a = assumed mean, then take the deviations of the items from a and call it d

Step 2:

Multiply each deviation by corresponding frequency amd obtain sigma fd

Step 3:

Multiply each fd by the corresponding d to get fd2 and obtain S fd2.

Step 4: