This is from my lecture notes and I should have clarified before leaving class.
How do you find the summation (xi - x bar) (yi - y bar) = 6640 summation (xi - xbar)2= 1239.88
x: 2 8 16 22 25 34 35 39
y: 30 75 165 200 110 250 225 225
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This is from my lecture notes and I should have clarified before leaving class.
How do you find the summation (xi - x bar) (yi - y bar) = 6640 summation (xi - xbar)2= 1239.88
x: 2 8 16 22 25 34 35 39
y: 30 75 165 200 110 250 225 225
Do you mean two separate things here?
and
?
Because that seems as:
If I'm right, then what you have to do is:
1. Find x bar and y bar, the mean of x and y respectively.
2. x_i is each value that x contains. x_i - x bar is (2 - x bar) or (8 - x bar), etc.
Summation of (x_i - x bar) is the mean, removed from each of the terms in x.
Here, it is:
(2 - x bar) + (8 - x bar) + (16 - x bar) + (22 - x bar) + (25 - x bar) +... + (39 - x bar)
3. The same goes for (y_i - y bar).
For the first one, multiply each result of (x_i - x bar) with (y_i - y bar) then add them together.
For example, do (2 - x bar)(30 - y bar) + ( 8 - x bar)(75 - y bar)
For the second one, square each (x_i - x bar) then add them up.
I just checked them, and I got the answers right :)
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