Chapter 17 Measures of Central Tendency Ex 17.4

Rajasthan Board RBSE Class 10 Maths Chapter 17 Measures of Central Tendency Ex 17.4

Find the mean (arithmetic) of following frequency distribution (Q. 1 – 4)
Question 1.

Solution :
Let A = 900, h = 20
Table of find arithmetic mean :

Arithmetic mean () = A +  × h = 900 +  × 20 = 900 – 8.8 = 891.2
Thus, required arithmetic mean = 891.2

Question 2.

Solution :
Let A = 63
Table to find arithmetic mean :

Arithmetic mean () = A +  = 63 –  = 63 – 0.35 = 62.65
Arithmetic mean = 62.59

Question 3.

Solution:
Let A = 275, h = 50

Arithmetic mean () = A +  × h = 275 –  × 50 = 275 – 8.75 = 266.25
Thus, required arithmetic mean = 266.25

Question 4.

Solution:
Let A = 42.5, h = 5

Arithmetic mean = A +  × h = 42.5 +  × 5 = 42.5 – 2.93 = 39.57
Thus, required A.M. = 39.57

Question 5.
Find mean of the following frequency distribution taking assumed mean 25.

Solution:
Let Assumed Mean (A) = 25
Table for calculation of arithmetic mean :

Arithmetic mean () = A +  = 25 +  = 25 – 1.75 = 23.25
Thus, required arithmetic mean = 23.25

Question 6.
In the following table, age distribution of patients suffering from a disease in a specify class in a city are given. Find average age (in yrs) per patient.

Solution :
Let assumed mean (A) = 29.5

Arithmetic mean () = A +  = 29.5 +  = 29.5 + 5.37 = 34.87
Thus, arithmetic mean = 34.87 yrs

Question 7.
Find mean from the following frequency distribution :

Solution :
Let A = 65, h = 10

Arithmetic mean () = A +  × h = 65 +  × 10
= 65 + 3.2 = 68.2
Thus, required A.M. = 68.2