How would I calculate this to get the probability. If a person bought 1 share of Google stock within the last year, what is the probability that the stock on that day closed at less than the mean for that year? Hint: You do not want to calculate the mean to answer this one. The probability would be the same for any normal distribution. This is from the close of NASDAQ date range of August 28, 2017 to August 27, 2018.