Find the mean of the marks obtained by 20 students in a classroom.
MarksFrequency872783531982922971812652983762
83.8
We know that,
Average or the mean value of a given number of observations is the sum of all observations divided by the number of observations.
⇒Mean=∑xifi∑fi
Now,
Marks(xi)Frequency(fi)xifi8721747832345315398219692218497197812162652130983294762152TOTAL201676
Mean
=∑xifi∑fi
=167620
=83.8
Thus, mean of the marks obtained by 20 students in a classroom is 83.8.