Calculate the standard deviation, ÏY, of the random variable Y from Exercise 3.5.4. Exercise 3.5.4 Consider a population of the fruit-fly Drosophila melanogaster in which

Calculate the standard deviation, σY, of the random variable Y from Exercise 3.5.4.
Exercise 3.5.4
Consider a population of the fruit-fly Drosophila melanogaster in which 30% of the individuals are black because of a mutation, while 70% of the individuals have the normal gray body color. Suppose three flies are chosen at random from the population; let Y denote the number of black flies out of the three. Then the probability distribution for Y is given by the following table:

Y (No. Black) Probability 0.343 0.441 0.189 0.027 1.000 3 Total