What is the standard deviation of the following data set:
1.3 2.4 1.5 2.6 1.3 2.4 1.3 9 9 1.8
First, calculate the mean, x̄, by adding the data items together and dividing by the the total number of data items, 10.
Using your data in the order you provided it, the standard deviation is now:
s = √ [ ( 1.3 - x̄ ) ² + ( 2.4 - x̄ ) ² + ..... + (1.8 - x̄ ) ² ] / 10