R=average of (X in Standard Units) multiplied by (y in Standard Units).
Formula
X plots = 1,2,3,4,5,6,7
1. Find average x
Average=4
2. Find SD of x
 SD=2

 3. Subtract the average from x Values;and divide it by the SD for each x values.
(do this for each x value... not all together)
Note: this will give you the values in standard units. (Example 1.5, .75, 1.75, etc)
4. Do the same thing for y values
5. multiply the values of each y and x corresponding values
(the values that were converted to standard units)
 Example:
 (x in standard units) X (y in standard units).
6. last take the average of the multiplied values (the product)
example:
.5 + 1  .75 + 2  1 + .75 +1
=0.714
r=0.71