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Home » Find the mean deviation from the mean and from a median of the following distribution:
Find the mean deviation from the mean and from a median of the following distribution:
CBSE | Class 11 | Exercise 32.3 | Maths | RD Sharma | Statistics
Find the mean deviation from the mean and from a median of the following distribution:
Marks 0-10 10-20 20-30 30-40 40-50
No. of students 5 8 15 16 6

 

Answer:

N = 50

N/2 = 50/2 = 25

The cumulative frequency just greater than 25 is 58, and the corresponding value of x is 28

Median = 28

RD Sharma Solutions for Class 11 Maths Chapter 32 – Statistics - image 64

= 1350/50

= 27

Class Interval xi fi Cumulative Frequency |di| = |xi – Median| fi |di| FiXi |Xi – Mean| Fi |Xi – Mean|
0-10 5 5 5 23 115 25 22 110
10-20 15 8 13 13 104 120 12 96
20-30 25 15 28 3 45 375 2 30
30-40 35 16 44 7 112 560 8 128
40-50 45 6 50 17 102 270 18 108
N = 50 Total = 478 Total = 1350 Total = 472

Mean deviation from Median = 478/50 = 9.56

Mean deviation from Median = 472/50 = 9.44

∴ Mean Deviation from the median is 9.56 and from mean is 9.44.

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