ok...i have my s1 exam coming(i mean we all do )...so i have a few doubts.......its from may/june 2007 qns 1....i dont get it at all
For part a)
r=Sxy/?(SxxSyy) = -808.917/?(113573 x 8.657) = -0.816 (3sf)
and by the way, the formula is given in the formula booklet.
b) Since the product moment correlation coefficient is a negative value, then this means that as one value increases, the other value decreases, so in this case, the houses become cheaper as they become further away from the station.
c) The product moment correlation coefficient is not affected by coding i.e. if you add, subtract, multiply or divide the original data for coding, it'll not change, so it's value is the same.