Question

. Calculate the mean deviation about mean for the following data :
Marks

obtained

10-20 20-30 30-40 40-50 50-60 60-70 70-80

Number of

students

2 3 8 14 8 3 2​

Answer 1

Answer:

This ur answer

Step-by-step explanation:

CI f

i

Mid−value

x

i

f

i

x

i

∣x

i

−

x

∣ f

i

∣x

i

−

x

∣

10−20 2 15 30 30 60

20−30 3 25 75 20 60

30−40 8 35 280 10 80

40−50 14 45 630 0 0

50−60 8 55 440 10 80

60−70 3 65 195 20 60

70−80 2 75 150 30 60

∑f

i

=40

∑f

i

x

i

=

1800 ∑f

i

∣x

i

−

x

∣=

400

⇒

x

=

∑f

i

∑f

i

x

i

=

40

1800

=45

⇒ Mean deviation about mean =

∑f

i

∑f

i

∣x

i

−

x

∣

=

40

400

=10