[alvarezangie]

Computers are often used to randomly generate the last digits of telephone numbers of potential survey subjects. The digits are selected so that they are all equally likely. The random variable x is the selected digit. Find the mean and standard deviation of the random variable x. I just want to make sure if I'm doing this right. For the mean I got .018 and deviation .3... I know there are 10 digits to choose from 0-9 with last digits I'm guessing so there are 10000 outcomes. Each 0-9 digit has 4/10000 probability, right? Please help me! I want to make sure I'm doing the first step right so I can move on.