Answer to Question #303766 in Statistics and Probability for kyut.

Question

number of computers sold per day at a local computer store are 0,1,2,3, and 4 with the probabilities 0.1, 0.2, 0.3, 0.2, and 0.2 respectively. Find the variance and standard deviation of the distribution

Answer 1

we first obtain the mean as below

mean= ( (0.1*0) + (0.2 *1) + (0.3 *2) + (0.2*3) + (0.2*4) ) = 2.2

Thus variance =( (0.1 *0²) + (0.2 *1²) + (0.3 * 2²) + (0.2*3²) +(0.2*4²) ) - (mean)²

= 6.4 - 4.84

= 1.56

standard deviation = (variance)^1/2 = (1.56)^1/2 = 1.2489996