Answer:
a. The mean of the data set is:
(146 + 153 + 155 + 160 + 161) / 5 = 155
b. The deviation from the mean for each data item is:
146 - 155 = -9
153 - 155 = -2
155 - 155 = 0
160 - 155 = 5
161 - 155 = 6
c. The sum of the deviations from the mean is:
-9 + (-2) + 0 + 5 + 6 = 0
Note that the sum of the deviations from the mean is always zero, since the positive deviations cancel out the negative deviations.