# A salesperson has found that the probability of making various numbers of sales per day is presented in the following table. Calculate the expected number of sales per day and the standard deviation of the number of sales.

Number of sales(Probability)

1(0.05) 2(0.16) 3(0.20) 4(0.25) 5(0.18) 6(0.10) 7(0.04) 8(0.02)