Notes Of Ecco Measures Of Dispersion For Class 11 Chapter 6 Download PDF

Chapter 6: Measures of Dispersion

1. Dispersion refers to the variation of the items around an average.

2. Objectives of Dispersion

a) To determine the reliability of an average.

b) To compare the variability of two or more series.

c) It serves the basis of other statistical measures such as correlation etc.

d) It serves the basis of statistical quality control.

a) It should be easy to understand.

b) Easy to calculate.

c) Rigidly defined

d) Based on all observations.

e) Should not be unduly affected by extreme values.

a) Range

b) Quartile Deviation

c) Mean Deviation

d) Standard Deviation

a) Coefficient of Range

b) Coefficient of Quartile Deviation

c) Coefficient of Mean Deviation

d) Coefficient of Variation

Range

It is the difference between the largest and smallest value of distribution.

Computation of Range

Range = L – S

1. It is simple to understand and easy to calculate.

2. It is widely used in statistical quality control.

1. It is affected by extreme values in the series.

2. It cannot be calculated in case of open end series.

3. It is not based on all items.

Inter quartile range is the difference between Upper Quartile (Q3) and Lower Quartile Q1.

Quartile deviation is half of inter quartile range.

Computation of Inter quartile range and quartile deviation

1. Easy to compute

2. Less affected by extreme values.

3. Can be computed in open ended series.

1. Not based on all observations

2. It is influenced by change in sample and suffers from instability.

Mean Deviation is defined as the arithmetic average of the absolute deviations [ignoring signs] of various items from Mean or Median.

1. Based on all observations.

2. It is less affected by extreme values.

3. Simple to understand and easy to calculate.

1. It ignores ± signs in deviations.

2. It is difficult to compute when deviations comes in fractions.

It is defined as the root mean square deviation.

1. Value of its deviation is taken from Arithmetic Mean.

2. + and – signs of deviations taken from mean are not ignored.

Coefficient of standard deviation:

i. Rigidly defined

ii. Based on all observations

iii. Takes Algebraic signs in consideration

iv. Amenable to further Algebraic treatment

i. Difficult to understand and compute.

ii. Affected by extreme items.

It is a graphical method of studying dispersion.

Lorenz curve is a cumulative percentage curve in which the percentage of frequency is combined with percentage of other items such as profit, income etc.

**1 mark questions**

1. What is range?

2. What is coefficient of variation?

3. What is Lorenz curve?

3 marks question

1.Mention any two merit and demerits each of Mean Deviation.

**4 marks questions**

1. Find out range and coefficient of range of the following series.

2. Find out Standard deviation (6) from the following data:

Please send your queries to ncerthelp@gmail.com you can aslo visit our facebook page to get quick help. Link of our facebook page is given in sidebar

- Chapter 6: Measures of Dispersion
- Chapter 1 Introduction
- Chapter 2 Collection of Data
- Chapter 3 Organization Of Data
- Chapter 5 Measures of Central Tendency
- Chapter 4 Presentation of Data
- Chapter 7 : Correlation
- Chapter 8: Index numbers
- Chapter 9 : Developing Projects in Economics
- Chapter 10: Indian Economy at the time of Independence
- Chapter 11: Development Policies and Experience
- Chapter 12 : Economic Reforms Since 1991
- Chapter 13: Poverty
- Chapter 15: Human Capital Formation
- Chapter 16: Employment growth, Information and Other issues

- NCERT Solutions for Class 9 Science Maths Hindi English Math
- NCERT Solutions for Class 10 Maths Science English Hindi SST
- Class 11 Maths Ncert Solutions Biology Chemistry English Physics
- Class 12 Maths Ncert Solutions Chemistry Biology Physics pdf

- Class 1 Model Test Papers Download in pdf
- Class 5 Model Test Papers Download in pdf
- Class 6 Model Test Papers Download in pdf
- Class 7 Model Test Papers Download in pdf
- Class 8 Model Test Papers Download in pdf
- Class 9 Model Test Papers Download in pdf
- Class 10 Model Test Papers Download in pdf
- Class 11 Model Test Papers Download in pdf
- Class 12 Model Test Papers Download in pdf

Copyright @ ncerthelp.com A free educational website for CBSE, ICSE and UP board.