Answer:
(i). Median Age= 58yrs
(ii). Value of x is 5.85 (approx. 6)
Step-by-step explanation:
Concept= Median and Mean of Grouped data
Given= Distribution Table and Mean
To find= Median and variable x
Explanation=
First we organize the data in our tabular form
Age Group No. of people([tex]f_{i}[/tex]) C.F Group Mark([tex]x_{i}[/tex]) [tex]f_{i} x_{i}[/tex]
15-25 8 8 20 160
25-35 10 18 30 180
35-45 15 33 40 600
45-55 25 58 50 1250
55-65 40 98 60 2400
65-75 24 122 70 1680
75-85 18 140 80 1440
∑[tex]f_{i}[/tex]=140 ∑[tex]f_{i} x_{i[/tex]=7710
(i). Median Age group of people enrolled in camps-
n=140(cf) , n/2= 70
Thus this observation lies between the age group 55-65(median class).
Lower Class limit(l)= 55, Class size(h)= 10, Frequency of median class(f)= 40
Cumulative frequency of class preceding the median class is(c) 58.
Formula to find median of grouped data is Median= [tex]l+{(n/2-c)/f} * h[/tex]
equating values we get, Median= 55+(70-58)/40 * 10= 55 +0.3*10= 55+3=58.
Median Age= 58yrs
(ii). Find x, when x people were added in group 65-75 and Mean was 58.
If x people were added in that group then number of people will become 24+x , Similarly the [tex]f_{i} x_{i}[/tex] value of 65-75 will become 1680+70x.
So now the new ∑[tex]f_{i} x_{i}[/tex]= 7710+70x .
Mean=∑[tex]f_{i} x_{i}[/tex]/∑[tex]f_{i}[/tex] , Equating the values we have ,
58= 7710+70x/140
=>8120=7710+70x
=>410=70x
=> x= 5.85 (approx. 6)
Therefor value of x is 5.85 (approx. 6)
Author:
nemesiosteele
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