Originally Posted by

**clarodina** Wanted to calculate the standard deviation manually quickly on quite a few data points. The data points is similar to below

Column1 Column 2

1.2

1.3 1.3

0.8 0.8

0.5 0.5

1.3 1.3

1.6 1.6

1.1

Column 2 is the same with column 1 except there is a new data point 1.1 and the first data point 1.2 is drop off. Does not want to recalculate the data one on one. Knowing the std dev of column 1, is there a quick formula to calculate the std dev of column 2 without manually recalculate each data point one on one?