Find the mean of the following distribution :Class30 – 4040 – 5050 – 6060 – 7070 – 80Frequency61381211

 Find the mean of the following distribution :

Class               30 – 40    40 – 50   50 – 60      60 – 70      70 – 80

Frequency             6            13             8               12              11

calculate class mark, mid value or mid -x [x]   then the product f*x

Class    f     x     f*x

30-40    6     35    210

40-50    13    45    585

50-60    8     55    440

60-70    12    65    780

70-80    11    75    825

Total  Σf =50,  Σfx= 2840

Mean = Σfx / Σf = 2840 / 50 = 56.8

for more explanation watch this video 

statistics arithmetic mean by direct method 

cbse 10th maths previous years question papers 2025 2026 question in statistics