Question

The marks out of 20 obtained by the students in an examination of maths are shown in the following frequency table. Find the arithmetic mean from the given below table

Answer 1

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● Mean ---

Sum of observations / No. of observations.

Observations --

5(2) + 8(5) + 10(8) + 12(10) + 15(12) + 18(2) + 20(1)

■ Sum :-

= 10 + 40 + 80 + 120 + 180 + 36 + 20

= 130 + 300 + 56

= 486

■ No. of observations :-

= 2 + 5 + 8 + 10 + 12 + 2 + 1

= 18 + 22 + 3

= 21 + 22

= 43

■ Mean :-

= 486/43

= 11.3

Hope it helps !

Answer 2

Answer:

Mean ---

Sum of observations / No. of observations.

Observations --

5(2) + 8(5) + 10(8) + 12(10) + 15(12) + 18(2) + 20(1)

■ Sum :-

= 10 + 40 + 80 + 120 + 180 + 36 + 20

= 130 + 300 + 56

= 486

■ No. of observations :-

= 2 + 5 + 8 + 10 + 12 + 2 + 1

= 18 + 22 + 3

= 21 + 22

= 43

■ Mean :-

= 486/43

= 11.3

Hope it helps !