Back to the National Survey of Youth study :
the actual covariance was
3028 where height is inches and the wages in
dollars.
Question: Suppose we measured all
the heights in centimeters, instead. There are 2.54 cm/inch?
Question: What will happen to the
covariance?
Solution: So let HI be height in inches and
HC be the height in centimeters, with
W – the wages.
Cov(HC,W) =
Cov(2.54 HI,W) = 2.54
Cov (HI,W).