I am learning A-Level Statistics together with my child and came across this problem:
I then double-checked with ChatGPT, and it gave this answer:
So who is right? Should we use Var(S) = $3^2$Var(S) as stated in the textbook, or Var(S) = 3*Var(S) as recommended by ChatGPT?
You're getting 3 different bars of soap, so it should be $S_1,S_2,S_3$ all identically distributed. So in this case, ChatGPT is correct.
Not $3S$, because you're not getting one bar of soap and cloning it three times. Where did you get the textbook?