3. LEARNING OBJECTIVES
• After reading this chapter, a student will be
understand different measures of central tendency
and Dispersion, i.e., Arithmetic Mean,Mean,Mode,
Geometric and Harmonic mean & Range, Mean
Deviation, Standard Deviation, Quartile Deviation,
Co efficient of variation
4. LEARNING OUTCOMES
• After the Chapter, The Students Shall be able to
Differentiate, Determine, and Identify the
relationships among Averages under Different
Series of Data and too State the Merits and
Demerits of Three Measures. The Students will
apply Measures of Dispersion to Sample Population
Data by Contrasting the Values of Standard
Deviation & The Mean Deviation, Synthesizing the
Mean,Standard,and Quartile Deviations into a
Useful Description of a Set of Data
5. SESSION - 40
• Merits & Demerits of Mean, Median and Mode
6. Merits and Demerits of Mean
Merits
• It is easy to compute and has a unique value.
• It is based on all the observations.
• It is well defined.
• It is least affected by sampling fluctuations.
• It can be used for further statistical analysis.
Demerits
• The mean is unduly affected by the extreme items
(outliers)
• It cannot be determined for the qualitative data such
as beauty, honesty etc.
• It cannot be located by observations on the graphic
method
7. Merits and Demerits of Median
Merits
• It is easy to compute. It can be calculated by mere
inspection and by the graphical method
• It is not affected by extreme values.
• It can be easily located even if the class intervals in the
series are unequal.
Demerits
• It is not amenable to further algebraic treatment
• It is a positional average and is based on the middle
item
• It does not take into account the actual values of the
items in the series
8. Merits and Demerits of Mode
Merits
• It is comparatively easy to understand.
• It can be found graphically.
• It is easy to locate in some cases by inspection.
• It is not affected by extreme values.
• It is the simplest descriptive measure of average.
Demerits
• It is not suitable for further mathematical treatment.
• It is an unstable measure as it is affected more by
sampling fluctuations.
• Mode for the series with unequal class intervals
cannot be calculated.
• In a bimodal distribution, there are two modal classes
and it is difficult to determine the values of the mode.
9. MCQs
(i) The most suitable average for qualitative
measurement is
(a) arithmetic mean
(b) median
(c) mode
(d) geometric mean
(e) none of the above
(ii) Which average is affected most by the presence of
extreme items?
(a) median
(b) mode
(c) arithmetic mean
(d) none of the above
10. MCQs
(iii) The algebraic sum of deviation of a set of n
values from A.M. is
(a) n
(b) 0
(c) 1
(d) none of the above
(iv) Which one of following merits of mean
a) It is easy to compute and has a unique value.
b) It is based on all the observations.
c) It is well defined.
d) All of above
11. MCQs
5 . The relationship of empirical between averages
a) Some time equal
b) Never equal
c) Always equal
d) None of these
13. REFERENCES
• S.P. Gupta, Sultan Chand and Sons Publications, 2017
• S. C. Gupta, Himalaya Publishing House,
Fundamentals of Statistics, 2018
• R.S.N Pillai and Bagavathi, S.Chand publications, 2010
