Question

The scores in History of 40 students in a class are represented through the table given below:
Score
50 - 56 | 57 - 63 | 64 - 70 | 71 - 77 | 78 - 84 | 85 - 91
Number of students
2
8
10
12
6
2​

Answer 1

We recall the concept of mean

The meanthe  is average of given data.

Given: Scores and no. of students

We write the data as follows

We write the classmarks as,$53,60,67,74,81,88$

And frequency as $2,8,10,12,6,2$

Thus $x_{i} f_{i}$ is $106,480,670,888,486,176$

Hence Mean$=\frac{2806}{40}$

                    $=70.15$        

Answer 2

Answer:

70.15

Step-by-step explanation:

We know, Mean= Sum of Terms/No. of Terms

Here Mean=∑ xifi/ ∑fi

Here fi means Frequency and xi represent classmarks

Class marks can be calculated by adding lower bound and upper bound and then dividing their sum by 2

Class marks will be , 53.60,67,74,81,88

Frequencies are 2,8,10,12,6,2

Mean=(53*2+60*8+67*10+74*12+81*6+88*2) / 40

Mean=2806

            40

Mean=70.15