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Originally posted by davidchin
I don't want to be doing your homework for you.
For starters, the x with the line over it means the average (mean) of all the x's. That is, you add up all 12 of the numbers (incomes) then divide by how many there are. In this case, there are 12 numbers and so you would add up all the numbers and then divide by 12 to get the value of the mean (the "x" with the line over it).
Then you take each individual number and subtract the mean from it, then square the result that you get.
Now that funny looking thing that sort of looks like a capital E (Σ) is really a capital greek "S" called sigma.
When you see that, you add up things for every repeating math operation. In this case, you would add up each of the twelve results that you got when you subtracted the mean from it and then squared what you got from there.
The exact result should come out as 744431.774266667 (or something close) on a calculator, but as the bottom is recommending, just use the approximation that is given.
I would use a spreadsheet program so I can keep track of all the numbers and do multiple mathematical calculations on them together while keeping them organized in nice rows or columns.
Hope this helps you get started.
Originally posted by davethebear
I applaud you all for the answers that you have come up with so far regarding this question.......
It would have been easier for me to read the telephone book.......
Maths was never my strong point.......