the mean of Marks secured by 65 students in division of A of class x is 58,48 students of division B is 54 and that of 70 students of division c is 51.find the approximate mean of the students of three divisions of class X.
Answers
Answer:
The approximate mean of all divisions of Class X = 54.3
Explanation:
Average = sum of observations / no. of observations
Sum of observations = Average * No. of observations
For Division A
No. of students = 65, Average marks = 58
Total marks = Average * No. of students
= 58 * 65
= 3770
For Division B
No. of students = 48, Average marks = 54
Total marks = Average * No. of students
= 54 * 48
= 2592
For Division C
No. of students = 70, Average marks = 51
Total marks = Average * No. of students
= 51 * 70
= 3570
For all the divisions, put together
Total marks = 3770 + 2592 + 3570
= 9932
Total number of students = 65 + 48 + 70
= 183
Overall average = Total marks / Total number of students
= 9932 / 183
= 54.3 (rounded off to one decimal place)
The approximate mean of marks secured by the students of all the three divisions of Class X is 54.3