the following data give the prices of seven textbooks randomly selected from a university bookstore. $89 $170 $104 $113 $56 $161 $147 Find the mean for these data. Calculate the deviations of the data values from the mean. Is the sum of these deviations zero? Mean = Deviation from the mean for $170 = Sum of these deviations = Solution mean = sum / 7 = 120 deviation = ( 89-120)^2 + (170-120)^2 + (104-120)^2+(113- 120)^2+(56-120)^2+(161-120)^2+(147-120)^2 =(961 +2500+256+49+4096+1681+729/8)^-2 = (10272 / 8)^-2 = 738.30.