I have downloaded stock quotes for google for the last year

I have downloaded stock quotes for google for the last year, so I have 228 closing quotes. I need the models or formulas to set up each question, then I think I can take it from there. For example, in question 1, I have already calculated the mean and standard deviation, if a person bought just one share in the last year, what is the probability equation?

Solution

you need to use the formula of Z standar

that is

Z = (x - miu) / sigma

you have sigma and mean