1. The mean and the standard deviation on Mrs Tuff’s last Year 12 Maths Methods test were
72 and 8 respectively. She thought these were too high. Mrs Tuff is going to transform the
scores so that the new mean is 65 with a standard deviation of 5.
If the random variable X represents the original scores and the random variable Y represents
the transformed scores, then Y = aX +b, where a and b are positive constants.
Find a and b
EDIT: a= 5/8 b=20
I only know how to find a, I have no clue how to find b =0
There's some formula that goes something like this:
=a^2VAR(X))
Old variance = 64 and new variance = 25.


That's the general idea, I vaguely remember the formula, and it worked out, but I'm not sure how to find b.
Maybe someone else is more familiar with this =p