Heights of 90 female students from Polytechnic of Seberang Peraj recorded in the following table. Height (in cm) Number of students 140.05 - 145.04 2 145.05 - 150.04 6 150.05 - 155.04 11 155.05 - 160.04 24 160.05 - 165.04 20 165.05 - 170.04 13 170.05 - 175.04 9 175.05 - 180.04 5 You are required to calculate: (a) Mean deviation (b) Variance (c) Pearson's coefficient of skewness 1 (PCS 1) (d) Pearson's coefficient of skewness 2 (PCS 2)