The pooled standard deviation refers to the combined standard deviation of two different groups of data values. Suppose that we have two data values of sizes n_1 and n_2 respectively. If the standard deviations of the two data sets are S_1 and S_2 respectively, then the pooled standard deviation can be calculated using the formula, S = \sqrt{\frac{(n_1-1)S_1^2+(n_2-1)S_2^2}{n_1+n_2}}

The pooled standard deviation calculator below gives the value of the combined standard deviation of two data sets.

**Sample 1**

**Sample 2**

**Pooled standard deviation = ** 7.739852

The pooled standard deviation is a kind of weighted average of the standard deviations of the two given samples. The pooled variance can be calculated by taking the square of the pooled standard deviation.