Question

9.
The following table gives the literacy rate (in percentage) of 35 cities. Find the mear
literacy rate.
Literacy rate in %
45-55
55-65
65-75
75-85
85-95
Number of cities
3
10
11
8
3
​

Answer 1

Step-by-step explanation:

Consider,literacy rate in % be the class intervals represented by C.I. and Number of cities be frequency represented by f .

calculate CLASS MARK(x) for each class interval which is given by the formula:-

x = Upper limit + Lower limit ÷ 2

therefore,class marks for each class interval are 50,60,70,80,90 respectively

Sum of all frequencies = 35

Now multiply class interval and frequency for each class and add them at the end

50×3 + 60 × 10 + 70 × 11 + 80 ×8 + 90 ×3=2430

Now,mean = sum of the product of all class marks and frequencies i.e. 2430÷Sum of all frequencies i.e. 35

therefore,mean = 2430÷35=69.43(approx.)