Three classes in a school having number of students 30,50 and 40 have average percentage marks as 50,60 and 55 respectivrly.find their combined mean of percentage marks.
Answers
Answer:
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Answer:
Concept:
The core value of a set of data is expressed by an average of the values in the list. It is defined mathematically as the ratio between the total number of units in the list and the sum of all the data. In statistics, the term "mean" also refers to the average of a particular set of numerical data.
Step-by-step explanation:
Given:
Three class in school having number of students such as 30,50 and 40.Their corresponding average percentage of marks as 50,60 and 55.
To Find:
Combined mean of percentage marks.
Solution:
Average = Total Marks / Total students
In a batch of 30 students , total marks = 30*60= 1800
In a batch of 50 students ,total marks = 50*50= 2500
In a batch of 40 students , total marks = 40*40 = 1600
Total Marks of all the students = 1800+ 2500+ 1600 = 5900
Total number of students = 30+ 50+ 40 = 120
Average Marks for all the students = Total Marks of all the students/Total number of students
Average Marks for all the students = 5900/120
= 49.167
Therefore, the combined mean of percentage marks is 49.167.
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