One of the AP Practice Test questions in Emma's book asked for the values of statistics of a data set which had been transformed by multiplying a constant and adding a constant. The only given information were the original mean and standard deviation. Rather than simply memorizing the rule, Emma and I worked through a proof that the new mean will be transformed in the same way that the original data values were transformed. I also showed the proof that the new standard deviation will be the original standard deviation multiplied by the constant.