Measures Of Dispersion

Question

Write down the steps involved in the calculation of mean deviation for the discrete series.

Solution

Steps : 1. Find out central tendency of the series (mean or median) from which deviations are to be taken.

2. Take deviation of different items in the series from central tendency ignoring signs (+,–). Express it as | dx | or (| dm |).

3. Multiply each deviation value by frequency facing it.

4. Add the multiplies and express it as Σ?(d).

5. Divide Σ?(d) by sum total of frequency. The resultant value will be mean deviation.

Some More Questions From Measures of Dispersion Chapter

A batsman is to be selected for a cricket team. The choice is between X and Y on the basis of their five previous scores which are:

X

Y

25

50

85

70

40

65

80

45

120

80

Which batsman should be selected if we want

(i) a higher run getter, or

(ii) a more reliable batsman in the team?

To check the quality of two brands of lightbulbs, their life in burning hours was estimated as under for 100 bulbs of each brand.

Life (in hrs)

No. of bulbs

Brand A

Brand B

0–50

15

2

50–100

20

8

100–150

18

60

150–200

25

25

200–250

22

5

100

100

(i) Which brand gives higher life?
(ii) Which brand is more dependable?

Average daily wage of 50 workers of a factory was Rs. 200 with a standard deviation of Rs. 40. Each worker is given a raise of Rs. 20. What is the new average daily wage and standard deviation? Have the wages become more or less uniform?

In the previous question, calculate the relative measures of variation and indicate the value, which in your opinion is more reliable.

If in the previous question, each worker is given a hike of 10% in wages, how are the mean and standard deviation values affected?

The sum of 10 values is 100 and the sum of their squares is 1090. Find the coefficient of variation.

Calculate the mean deviation about mean and standard deviation for the following distribution:

Classes

Frequencies

20–40

3

40–80

6

80–100

20

100–120

12

120–140

9

50

For Daily Free Study Material Join wiredfaculty

Measures Of Dispersion

Write down the steps involved in the calculation of mean deviation for the discrete series.

Some More Questions From Measures of Dispersion Chapter

A batsman is to be selected for a cricket team. The choice is between X and Y on the basis of their five previous scores which are:

X

Y

25

50

85

70

40

65

80

45

120

80

Which batsman should be selected if we want

(i) a higher run getter, or

(ii) a more reliable batsman in the team?

Average daily wage of 50 workers of a factory was Rs. 200 with a standard deviation of Rs. 40. Each worker is given a raise of Rs. 20. What is the new average daily wage and standard deviation? Have the wages become more or less uniform?

In the previous question, calculate the relative measures of variation and indicate the value, which in your opinion is more reliable.

If in the previous question, each worker is given a hike of 10% in wages, how are the mean and standard deviation values affected?

The sum of 10 values is 100 and the sum of their squares is 1090. Find the coefficient of variation.

Calculate the mean deviation about mean and standard deviation for the following distribution:

Classes

Frequencies

20–40

3

40–80

6

80–100

20

100–120

12

120–140

9

50

A measure of dispersion is a good .supplement to the central value in understanding a frequency distribution. Comment

Define dispersion.

How many methods are there to calculate dipersion?

Mock Test Series

NCERT Sample Papers

Entrance Exams Preparation

Phone Number

Email Address

Location

Life (in hrs)	No. of bulbs
	Brand A	Brand B
0–50	15	2
50–100	20	8
100–150	18	60
150–200	25	25
200–250	22	5
	100	100

Classes	Frequencies
20–40	3
40–80	6
80–100	20
100–120	12
120–140	9
	50

For Daily Free Study Material Join wiredfaculty

Measures Of Dispersion

Write down the steps involved in the calculation of mean deviation for the discrete series.

Some More Questions From Measures of Dispersion Chapter

A batsman is to be selected for a cricket team. The choice is between X and Y on the basis of their five previous scores which are: X Y 25 50 85 70 40 65 80 45 120 80 Which batsman should be selected if we want (i) a higher run getter, or (ii) a more reliable batsman in the team?

Average daily wage of 50 workers of a factory was Rs. 200 with a standard deviation of Rs. 40. Each worker is given a raise of Rs. 20. What is the new average daily wage and standard deviation? Have the wages become more or less uniform?

In the previous question, calculate the relative measures of variation and indicate the value, which in your opinion is more reliable.

If in the previous question, each worker is given a hike of 10% in wages, how are the mean and standard deviation values affected?

The sum of 10 values is 100 and the sum of their squares is 1090. Find the coefficient of variation.

Calculate the mean deviation about mean and standard deviation for the following distribution: Classes Frequencies 20–40 3 40–80 6 80–100 20 100–120 12 120–140 9 50

A measure of dispersion is a good .supplement to the central value in understanding a frequency distribution. Comment

Define dispersion.

How many methods are there to calculate dipersion?

Mock Test Series

NCERT Sample Papers

Entrance Exams Preparation

A batsman is to be selected for a cricket team. The choice is between X and Y on the basis of their five previous scores which are:

X

Y

25

50

85

70

40

65

80

45

120

80

Which batsman should be selected if we want

(i) a higher run getter, or

(ii) a more reliable batsman in the team?

Calculate the mean deviation about mean and standard deviation for the following distribution:

Classes

Frequencies

20–40

3

40–80

6

80–100

20

100–120

12

120–140

9

50