Question b) What is the standard deviation of the number of lights on a floor that are replaced?

The maintenance staff of a large office building regularly replaces fluorescent ceiling lights that have gone out. During a visit to a typical floor, the staff may have to replace several lights. The manager of this staff has given the following probabilities to the number of lights (identified by the random variable Y) that need to be replaced on a floor. Use the table to complete parts (a) through (e) below. Y 0 1 2 3 4 P(Y = y) 0.30 0.25 0.15 0.20 0.10 (a) How many lights should the manager expect to replace on a floor? 1.55 lights (Round to two decimal places as needed.) (b) What is the standard deviation of the number of lights on a floor that are replaced? lights (Round to two decimal places as needed.)