for a group of four men , the probability distribution for the number x who live through the next year is as given in the accompanying table. Find out the mean and the standard deviation
x | p(x)
0 | 0.05
1 | 0.15
2 | 0.45
3 | 0.25
4 | 0.10

Use the formulae that you know of. What do you get?

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