An incomplete frequency distribution is given below
Variate
Frequency
10 - 20
12
20 - 30
30
30 - 40
?
40 - 50
65
50 - 60
45
60 - 70
25
70 - 80
18
Total
229
Median value is $$46,$$ the missing frequency is:
A.
32
B.
35
C.
34
D.
26
Answer :
34
Solution :
Median $$= 46$$ which lies in $$40 – 50$$ class
Median $$ = l + h\frac{{\left\{ {\frac{n}{2} - {C_f}} \right\}}}{f}$$
where $$f =$$ frequency of median-class
$${C_f} = $$ cumulative frequency of the class preceding the median class.
$$\eqalign{
& \therefore \,46 = 40 + 10\frac{{\left[ {\frac{{229}}{2} - \left( {x + 42} \right)} \right]}}{{65}} \cr
& {\text{where }}x = {\text{ frequency of class }}30 - 40 \cr
& \Rightarrow x = 33.5 = 34 \cr} $$
Releted MCQ Question on Statistics and Probability >> Statistics
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