Example Find the number of pair of observations
from the following data.
r = 0.25, S
(xi - x ) ( yi - y ) = 60, sy
= 4, S ( xi - x )2 = 90.
Solution: Given - r = 0.25
If the values of x and y are very big, the calculation becomes
very tedious and if we change the variable x to u =
and y to
where x0 and y0 are the assumed means
for variable x and y respectively, then rxy = ruv
The formula for r can be simplified as