Stats: Need help understanding where the sum of x^2 comes from

[smaan]

Homework Statement

I have no idea where the sum of x^2 comes from, from the information I posted. I know it must be something pretty simple but its completely going over my head. In the picture that I've attached, I am wondering where the 2431.72, 4901.66, and 3252.44 come from. Thank you for any help.

Homework Equations

The Attempt at a Solution

 

[SteamKing]

What did you try to get Sum(x)? Sum(x^2)?

 

[smaan]

What did you try to get Sum(x)? Sum(x^2)?

I tried squaring x, but obviously that is not correct.

 

[SteamKing]

Did you try, you know, adding up the columns of figures? That's what Sum(x) means. The other one is trickier: you've got to square each number, and then add them up.

 

[DeeNos]

The sum of x^2 is a common calculation used in statistics, specifically in the context of calculating variance and standard deviation. It represents the sum of the squared values of a set of numbers. In the picture attached, it appears that the sum of x^2 is being used to calculate the variance of a data set. The numbers 2431.72, 4901.66, and 3252.44 are likely the squared values of the data points in the data set. Without more context or information, it is difficult to determine exactly where these specific numbers come from. However, understanding that the sum of x^2 is used to calculate variance can help provide some insight into their origin.