Page 166 - DMGT404 RESEARCH_METHODOLOGY

Research Methodology

Notes
Example: For the data 103, 50, 68, 110, 105, 108, 174, 103, 150, 200, 225, 350, 103 find the
range, coefficient of range and coefficient of quartile deviation.
Solution:
Range = H – L = 350 – 50 = 300

H  L 300
Coefficient of range   0.7
H  L 350 50

To find Q and Q we arrange the data in ascending order:
1 3
50, 68, 103, 103, 103, 103, 105, 108, 110, 150, 174, 200, 225, 350,

n  1 14
  3.5,
4 4

n
3( 1)
 10.5
4
 Q = 103 + 0.5 (103 – 103) = 103
1
Q = 174 + 0.5 (200 – 174) = 187
3
84
Coefficient of QD =  0.2896
290
Self Assessment

Fill in the blanks:
14. ................................ is the spread of the data in a distribution.
15. ................................ is a measure of the average squared distance between the mean and
each term in the population.

8.4 Summary

 Descriptive statistics are used to describe the basic features of the data in a study.
 They provide simple summaries about the sample and the measures.
 Together with simple graphics analysis, they form the basis of virtually every quantitative
analysis of data.
 Descriptive Statistics are used to present quantitative descriptions in a manageable form.
In a research study we may have lots of measures.
 When summarizing a quantity like length or weight or age, it is common to answer the
first question with the arithmetic mean, the median, or, in case of a unimodal distribution,
the mode.
 Sometimes, we choose specific values from the cumulative distribution function called
quantiles.
 The most common measures of variability for quantitative data are the variance; its square
root, the standard deviation; the range; interquartile range; and the average absolute
deviation (average deviation).

160 LOVELY PROFESSIONAL UNIVERSITY