Mean

IMPORTANT

Mean: Overview

This topic covers concepts such as Measures of Central Tendency, Mean, Mean for Ungrouped Data, Mean for Grouped Data, Direct Method for Finding the Mean of Grouped Data, Assumed Mean Method for Finding the Mean of Grouped Data, etc.

Important Questions on Mean

MEDIUM
IMPORTANT

Three values of a variable are 4, 5 and 7, if their frequencies are p-2, p + 1 and p-1 respectively and mean is 5.4, then value of p is:

EASY
IMPORTANT

The average of 9 observations is 15. If one more observation be added, the average becomes 16. Find the 10 th observation.

EASY
IMPORTANT

If the average of 10 observations x1, x2, , x10 be 20 then find the average of x1+4, x2+8, x3+12, x10+40 

EASY
IMPORTANT

Find the mean of first n even positive integers.

MEDIUM
IMPORTANT

The following table shows the number of students and the time they utilised daily for their studies. Find the mean time (in hours), spent by students for their studies:

Time hours No. of students
0-2 8
2-4 14
4-6 18
6-8 10
8-10 10

EASY
IMPORTANT

For a certain frequency distribution, the values of mean and median are 72 and 78 respectively. Find the value of mode.

MEDIUM
IMPORTANT

Find the mean age of 100 residents of a colony from the following data.

Age

(in years)

0-10 10-20 20-30 30-40 40-50 50-60 60-70
No. of
Persons
10 15 25 25 10 10 5

MEDIUM
IMPORTANT

The following table shows the number of students and the time they utilised daily for their studies. Find the mean time (in hours), spent by students for their studies:

Time hours No. of students
0-2 8
2-4 14
4-6 18
6-8 10
8-10 10

MEDIUM
IMPORTANT

Find the mean of the following frequency distribution:-

Class 0-10 10-20 20-30 30-40 40-50
fi 6 10 13 7 4

HARD
IMPORTANT

The given is the marks obtained by 70 boys in a class test.

Marks 30-40 40-50 50-60 60-70 70-80 80-90 90-100
No. of boys 10 12 14 12 9 7 6

Calculate the mean of marks rounded off to two decimal places.

EASY
IMPORTANT

When calculating the means of grouped and ungrouped data, there will be a variation.

EASY
IMPORTANT

Define Arithmetic mean and give their two demerits.

HARD
IMPORTANT

Find the arithmetic mean from the following frequency distribution:

Weight (in kg) 40-44 44-48 48-52 52-56 56-60 60-64
No. of persons 5 6 5 9 3 2

MEDIUM
IMPORTANT

Find the arithmetic mean of the following distribution:

x 1 2 3 4 5 6
f 45 25 19 8 2 1

MEDIUM
IMPORTANT

Find the arithmetic mean of the following distribution:

x 19 21 23 25 27 29 31
f 13 15 16 18 16 15 13

MEDIUM
IMPORTANT

Find the arithmetic mean of the following distribution

x 10 15 17 20 22 30 35
f 5 10 2 8 3 6 6

EASY
IMPORTANT

Find the arithmetic mean of the following distribution

x 5 6 7 8 9
f 4 8 14 11 3

EASY
IMPORTANT

 Give difference between arithmetic mean and weighted arithmetic mean

EASY
IMPORTANT

Positional mean is:

HARD
IMPORTANT

Find the mean of the following frequency distribution.

Class interval 40-50 50-60 60-70 70-80 80-90 90-100
Frequency 10 25 28 12 10 15