Question

find median
Mark's 10-20 20-30 30-40 40-50 50-60 60-70 70-80 80-90
frequency 15 21 35 52 49 17 3 1​

Answer 1

Explanation:

marks frequency C. F

10-20 15 15

20-30 21 36

30-40 35 71

40-50 52 123

50-60 49 172

60-70 17 189

70-80 3 192

80-90 1 193

we take class 40-50

L1 = 50

Cf = 71

f/2 = 193/2 = 96.5

c = 50-40 = 10

fm = 52

median = L1 + (f/2 - Cf /fm) c

= 50 + (96.5 - 71/52)10

= 54.90

Median = 54.90