## Question 896:

1## Answer:

No answer provided yet.### Files Available For Download

The mean of a random variable is the same thing as the expected value over the long term. To find it you simply sum the values of x times their probability of occurrence. See the attached spreadsheet for the calculations. For the first value, the expected value is 2*.15 = .3 and so on. When you add up all the expected values you get 6.30 which is the answer to part a.The standard deviation can be found by

- Squaring the mean value we found in part a 6.30*6.30 = 39.690
- Summing up all the deviations which can be found by squaring the X column value and multiplying it times the P(X) column. So for the first one the deviation value is 2*2*.15 = .6.
- Next we add up all the deviations and we get 47.4
- Next we find the variance which is found as the sum of deviations - mean squared = 47.4-39.690 = 7.710
- Finally we take the square root of the variance to get the standard deviation = SQRT(7.710) = 2.777