dle- the the ine 5th 70 70-80 80-90 90-100 Total Here m N 80 2 2 = 40. f 10 (40-32) 20 the median is 34 % of marks. = 30 + 1 0 80 To find the class-interval in which this The cumulative frequency upto The cumulative frequency upto .. the 40th observation is in the class interval 30-40, which is the median class. In the usual notation, /1 = 30, 12 = 40, f= 20, m = 40 and cf = 32. (12-11) (m-cf) M = 1 + frequency lies. 30% marks, is 32 and 40% marks is 52. 78 79 80 80 34