Chapter 3:Pair of Linear Equations in Two Variables

Chapter 5: Arithmetic Progression

Chapter 8: Introduction to Trigonometry

Chapter 9:Some Applications of Trigonometry

Chapter 12:Area Related to Circles

Statistics

We know the

Mean =
162
/
20

= 8.1We use this method because value of f_{i} and X_{i} is very small

Consider the following distribution of daily wages of 50 workers of a factory

Find the mean daily wages of the workers of the factory by using an appropriate method

Mean x̄ ==

150 + (20 ×

-12
/
50

)= 150 – 4.8 = 145.20

The mean daily wage of the workers = 145.20

Mean = =

(752+20f)
/
(752+20f)

)Here mean= 18

⇒ 18 =

(752+20f)
/
(752+20f)

)⇒ 18(44+f) = (752+20f)

⇒ 792+18f = 752+20f

⇒ 792+18f = 752+20f

⇒ 792 – 752 = 20f – 18f

⇒ 40 = 2f

⇒ f = 20

f = 20

Mean = x̄ =

A = 75.5 , h=3

= 75.5 + 3×(

4
/
30

)= 75.5 +

4
/
30

= 75.5 + 0.4

= 75.9

Find the mean number of mangoes kept in a packing box. Which method of finding the mean did you choose?

Mean = x̄ = A +h

∑fidi
/
∑fi

= 57 + 3(

75
/
400

)= 57 + 0.1875 = 57.19

Find the mean daily expenditure on food by a suitable method

Find the mean daily expenditure on food by a suitable method

Here a=225 , h=50

Mean =

= 225+50(

-7
/
25

)= 225-14

= 211

Find the mean concentration of SO

Mean = x̄ =

=

2.96
/
30

= 0.099 ppm

Mean =

=

499
/
40

= 12.48

Mean =

here a=70 , h =10

= 70 + 10 x(

-2
/
35

)
= 69.42