Question

The number of telephone calls received at an exchange in 245 successive one-minute intervals are shown in the following frequency distribution. Compute the mean deviation about the median.

No. of calls	Frequency
0	14
1	21
2	25
3	43
4	51
5	40
6	39
7	12

Answer 1

No. of calls	f	c.f	|D|	f|D|
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
	N = 245			Σf|D| = 366