Probability of 2 fives out of two dice roles is 1/36 (1 possibility out of 62 possible rolls
Probability of one 5 out of two dice is 11/36 1,2,3,4,6 - 5 twice ( because 1 on die 1 and 2 on die 22 is matched be 1 on die 2 and 2 on die 1) 10/36
Probability of no 5's is 1-11/36 or 5/6*5/6 = 25/36
The average is the sum of number of 5's times the probability of that number of 5's
(Expected value of number of 5's or mean value)
Variance: Calculate the sum of the number of 5's squared times the probability of 5's (Sum of x2P(x)
Take the sum of the x2P(x) and subtract the mean squared.
S.D = sqrt(Var)
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