Question: Two "math geeks" who work at your precinct, Victoria and Dave, are in an argument. Dave is arguing that if you increase every score in a sample by two, you only change the mean and you do not change the standard deviation. Victoria is arguing that if you increase every score in a sample by two, you change both the mean and the standard deviation. Knowing that you have taken a statistics course at Tiffin, they turn to you to settle the argument. Who is correct? Show mathematical proof.