Time left 1 The following table gives the cost of household's electricity bills during the spring months, in dollars. The households are in the same area and are similar in size. The first column represents houses with central a and the second column represents houses with window units. (Round answers to one decimal place) Central Air Window Unit 32 16 65 87 85 98 100 120 67 42 40 20 70 80 BO 90 110 70 40 a) The mean for the Central air column is b) The mean for the Window Unit column is c) The standard deviation for the Central Air column is