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Home » The number of telephone calls received at an exchange in 245 successive on2-minute intervals is shown in the following frequency distribution:
The number of telephone calls received at an exchange in 245 successive on2-minute intervals is shown in the following frequency distribution:
CBSE | Class 11 | Exercise 32.2 | Maths | RD Sharma | Statistics
The number of telephone calls received at an exchange in 245 successive on2-minute intervals is shown in the following frequency distribution:
Number of calls 0 1 2 3 4 5 6 7
Frequency 14 21 25 43 51 40 39 12

Compute the mean deviation about the median.

 

Answer:

Median is the even term, (3+5)/2 = 4

Median = 8

xi =Number of calls

fi = Frequency

xi fi Cumulative Frequency |di| = |xi – M|

= |xi – 61|

 fi |di|
0 14 14 4 56
1 21 35 3 63
2 25 60 2 50
3 43 103 1 43
4 51 154 0 0
5 40 194 1 40
6 39 233 2 78
7 12 245 3 36
Total = 366
Total = 245

N = 245

 

= 1/245 × 336

= 1.49

∴ The mean deviation is 1.49.

i

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