Question

The following table gives the frequency distribution of the marks of 400 candidates in and examination ?
Marks:- 0-10 10-20 20-30 30-40 40-50 50-60 60-70 70-80 80-90 90-100
No: of candidates: 5. 20. 40. 70. 85. 65. 50. 35. 20. 10

Answer 1

Explanation:

The formula used for arithmetic mean of grouped data by step deviation method is,

X

=A+

∑f

∑fu

×i

A= Assumed mean of the given data

∑ = Summation of the frequencies given in the grouped data

∑fu = Summation of the frequencies and deviation of a given mean data

u=

i

(x−A)

i= Class interval width

X

= arithmetic mean

X

=45+

70

63

×10

=45+9

=54