Slope
The slope of the leastsquares line.
The formula:
Sample 1:
Give the set of X and Y values where X and Y can represent any correlated values below:
X 
Y 
1 
2 
2 
4 
3 
6 
4 
8 
5 
10 
6 
12 
7 
14 
8 
16 
9 
18 
10 
20 
Sample table
Computing the Slope

Solve the parts of the formula:
n =count of items, equal to 10
= multiply all x and y items and get the sum = 770
1x2 + 2x4 + 3x6 + 4x8 + 5x10 + 6x12 + 7x14 + 8x16 + 9x18 + 10x20 = 770
= sum of x items = 55
= sum of y items = 110
= get the square of all x items and sum up the values. To square a number also means to multiply the number by itself.
1x1 + 2x2 + 3x3 + 4x4 + 5x5 + 6x6 + 7x7 + 8x8 + 9x9 + 10x10 = 385
= get the sum of all items in x and get the square = 55 * 55 or 3025

Substitute the known values in the formula and computed for the Slope:
Slope = [10(770) – 55(110)]/[10(385) – 3025]
Slope = [7700 – 6050]/38503025]
Slope = 1650/825
Slope = 2