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The Number of Telephone Calls Received at an Exchange per Interval for 250 Successive One Minute Intervals Are Given in the Following Frequency Table: - Mathematics

The number of telephone calls received at an exchange per interval for 250 successive one minute
intervals are given in the following frequency table:

No. of calls(x) 0 1 2 3 4 5 6
No. of intervals (f) 15 24 29 46 54 43 39

Compute the mean number of calls per interval.

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Solution

Let be assumed mean (A) = 3

No. of calls

(x1)

No. of intervals

(f1)

u1 = x1 - A

(A = 3)

f1u1
0 15 -3 -45
1 24 -2 -47
2 29 -1 -39
3 46 0 0
4 54 1 54
5 43 2 86
6 39 3 47
  N = 250   `sumf_1u_1=135`

Mean number of cells `=A+(sumf_1u_1)/N`

`=3+135/250`

`=(750 + 135)/250`

`=885/250`

= 3.54

  Is there an error in this question or solution?
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APPEARS IN

RD Sharma Class 10 Maths
Chapter 15 Statistics
Exercise 15.2 | Q 1 | Page 13
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