MODULE 5
Descriptive Statistics
A descriptive statistic (in the count noun sense) is a
summary statistic that quantitatively describes or
summarizes features from a collection of information
while descriptive statistics (in the mass noun sense) is
the process of using and analyzing those statistics.
Descriptive statistics is distinguished from inferential (or
inductive statistics) by its aim to summarize a sample
rather than use the data to learn about the
population that the sample of data is thought to
represent. This generally means that descriptive
statistics, unlike inferential statistics, is not developed on
the basis of probability theory and are frequently nonparametric statistics. Even when a data analysis draws
its main conclusions using inferential statistics,
descriptive statistics are generally also presented. For
example, in papers reporting on human subjects,
typically a table is included giving the overall sample
size, sample sizes in important subgroups (e.g., for each
treatment or exposure group), and demographic or
clinical characteristics such as the average age, the
proportion of subjects of each sex, the proportion of
subjects with related co-morbidities, etc
Maximum and Minimum
Measures of Central Tendency
Mean
Summary Measures
Median
Measures of Location
Mode
MODULE 6
Descriptive Statistics: Measures of Variations
Comparing Standard Deviation
Range (R)
Coefficient of Variation (CV)
Interquartile Range (IR)
Comparing Coefficient of Variation (CV)
Variance
Measures of Skewness
Standard Deviation
Remarks on Standard Deviation
What is Symmetry?
Quartiles
Measures of Kurtosis
Measures of Variation
MODULE7
Descriptive Statistics: Measures of Positions
Percentiles
Measures of Variation
Deciles