erm hi. I thought i'd try and explain how coding affects pmcc- it doesn't- NOT AT ALL. But for some strange reason, sxx/syy/sxy is affected. they aren't affected by +/- but are affected by multiplication and division.
I remember it this way: sxx is related to variance. and variance is std dev. squared. so the coding on the values affects sxx as a square. im not sure if im making much sense, so i'll give an example.
syy= 3535237.5
y is coded to h=y/1000
the std dev. would change from say, 300 to 0.3 - although they're very unrealistic i hope u get my point.
shh would then be equal to 3535237.5 divided by 1000 squared--> 3.5352375
hope this helps. i think it's right- i had to figure it out 4rm the mark scheme cos i was never taught it. Good luck tomorrow