Question

Find the median from the following data: $\begin{array}{cccccccccc}\text{Xi}& 5& 10& 15& 20& 25& 30& 35& 40& 45\\ \text{Frequency}& 7& 10& 16& 32& 24& 16& 11& 5& 2\end{array}$

Answer 1

Sol:

Xi	Frequency fi	C.F
5	7	7
10	10	17
15	16	33
20	32	65
25	24	89
30	16	105
35	11	116
40	5	121
45	2	123
	N=∑fi=123

Here N =123 (which is odd )

=> (N+1)/2 = 62
so median will we the 62th observation
from the table we can see both 62th observation corresponding to 20 in column of Xi.
median of the given data is 20.