Question

find out the Arithmetic mean of the following data:
Class/Size : 2 3 4 5-7 7-10 10-15 15-20 20-25
F : 1 2 2 3 5 10 8​

Answer 1

Answer

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Size of the itemf      10−154      15−208      20−2518      25−3030      30−3520      35−4010      40−455      45−502Modal class is 25−30 since it has the maximum frequency.

Lower limit of the modal class l=25

Frequency of the modal class f=30

Frequency of the preceding modal class f1=18

Frequency of the class reducing the modal class f2=20

Class width c=5

Mode =l+(2f−f1−f2f−f1)×c

          =25+(60−18−2030−18)×5=25+2212×5

          =25+2260=25+2.73=27.73

Mode =27.73