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The following data shows the weekly income of workers Weekly Income($) 35-39 40-44 45-49 50-54 55-59 60-64 65-69 70-74 No. of workers 151 131 17 29 11 10 a) Using above grouped data with 8 classes with group frequencies f, and class midpoints m, show that ) _, f, (m, - 2) = 0 b) Find lower, median and upper quartiles. ii. Using above data explain the empirical relationship between mean, median and mode. Also give comments about the distribution of the data