Variance and Standard deviation

Question

What is the variance and standard deviation for 10,9,9,8,8,8,8,6?

Answer 1

SD= 1.16496 
Variance= 1.35714 

To calculate the standard deviation there are four simple steps:

1. Find the average (also known as the mean) of the data set.
2. For each individual number, subtract the Mean and square the result.
3. Find the average of the results from step 2.
4. Take the square root of that and you are done!

 

To calculate the variance there are three steps.

1.Find the average (also known as the mean) of the data set)
2.subtract the Mean and square the result
3. work out the average of those squared differences. 

 

Answer 2

You can also start out by taking the variance (best to do first), then take the square root of it to get the standard deviation. aka sigma = σ

 

Variation is properly defined above