I need to know the standard deviation and how to get it for the following set of numbers. {10, 11, 10, 12, 11, 10, 11, 11, 12, 13, 11, 10, 14}

2 answers

The standard deviation is the sqrt(sum(mean - i)^2 / (n-1)), where i takes on the value of each element in the set, and n is the number of elements in the set.

Start by finding the mean. Then for each element in the set, find the difference from the mean and square it. Find the sum of those differences, divide it by (n-1), and take the square root.
In case you didn't understand Marth's directions, you need to find the sum of those squared differences.

Since the mean of any distribution is a fulcrum, the sum of the differences of individual scores from the mean always = 0.

I hope this helps a little more.