These slides describe introduction of statistics.

1. Description of Statistics
Meanings of Statistics: The word Statistics seems to have been come from Latin word “Status”, an Italian
word “Statista”or a German word “Statistik”. Interesting thing is that all these words from different languages
have the same meaning i.e. “apolitical state” . This means information that is useful to the state/country etc. For
example: information a boutthe size of the population ,armed forces, noof weapons, noof horses etc .But today
this word has quite different meanings and can be divided into three main categories.
1. Numerical Facts Systematically Arranged
It is collection of numerical measurements or observations related to some field of interest for some purposes.
These observations may be taken from sample or population. The observations about the wages of workers are
called statistics of wages. The prices of various items taken from market are called statistics of prices. Statistics
of prices, Statistics of road accidents, Statistics of crimes, Statistics of birth, Statistics of deaths, Statistics of
educational institutions etc.
2. Statistics as a subject: In singular sense ,we consider statistics as a subject. So
,Statistics is a science that provides methods/techniques which are used to collect, present ,analyze and interpret
the numerical data and to reach any decision in the face of uncertainty.

2. 3. Statistics as plural of statistic: Any numerical value such as mean
,median, S .Detc. computed from sample data is called a statistic. When we have more than one such statistic’s.
We use the word statistics as plural of statistic.
Population: In literary sciences by population we mean to tell number of individuals/ inhabitants living in a
wEll-defined area. But in statistical sciences by population we mean total number of individuals /objects /items
having some common characteristics. Size of the population is represented by N.
A population may be finite or infinite. A population is said to finite if its countable e.g. total
number of students of FCC Lahore , Number of patients admitted at Jinnah hospital in September 2010,
Number of car accidents in 2009 etc .Similarly, a population is said to be infinite if it is uncountable, e.g.
population of throws of a die, population of stars on the sky etc.
Sample: A small part of population which is selected randomly and it holds the characteristic of the respective
population is called sample. Size of the sample is represented by n.
Suppose ,a Statistics class consists of 40 students and we are interested to select 10 students
randomly to get some kind of information. In this example 40 students is the size of population i.e. N=40 and 10
students chosen at random is the size of the sample i.e. n=10.
Parameter and Statistic: Any numerical quantity such as an average, measure of variability
etc. computed from population is called a parameter while any numerical quantity such as an average, measure
of variability etc. computed from sample is called statistic.

3. Parameter is a fixed value, while statistic is a variable quantity and it changes from one sample to another.
Parameters are usually denoted by Greek letters such as α, β, γ etc., while statistics are
usually denoted by English letter such as a, b, c etc.
Types of Statistics
Descriptive Statistics:
Methods of organizing, summarizing and presenting data in an informative way. Presenting the numerical
information in the form of number, graphs and tables.
Inferential Statistics:
A decision, estimate, prediction, or generalization about a population, based on a sample. To estimate the population
parameter on the basis of the sample statistic.
Bio statistics
The use of statistical methods in biological sciences is called biometry or Biostatistics.
Variable and Constant:

4. A quantity which varies from one individual/object/unit to another individual/object/unit is called a variable. While a
quantity which does not vary from one individual/object/unit to another individual/object/unit is called a constant.
Variables are denoted by capital letters X ,Y, Z etc. ,while constants are denoted by small letters a, b, c etc .A variable
can assume many values. A set of all possible values of a variable is called its sample space. A constant contains only
one value in its sample space.
Examples: The age of a person is a variable, as it varies from person to person. The height of an individual is a
variable which changes from one individual to another. Number of noses and number of eyes of each person etc. are
the examples of constants.
Classification of Variables: Variables may be classified as quantitative and qualitative
depending upon the characteristic of interest(See Figure).A variable is called a quantitative variable if the
characteristic of interest can be expressed numerically such as age, height, weight ,blood pressure, income or
number of children .On the other hand, a variable is called qualitative variable if the characteristic of interest
cannot expressed numerically such as education, sex, eye color, intelligence, poverty etc. A qualitative variable
is also called an attribute. A quantitative variable further more can be categorized as discrete and continuous
variable.

5. Variable
Qualitative Quantitative
Discrete Continuous
Discrete and Continuous Variables
A variable that can take/ assume only integer type or fixed values is called discrete variable e.g. number of
family members ,number of patients, shoe or shirt sizes. Similarly, a variable that can take/assume any value in
an interval is called a continuous variable. Heights, weights, temperatures are examples of continuous
variables.
Collection of data
The basic step in any investigation is collection of data. The data may be collected from the whole population
or sample. But in most of cases data are collected through samples. The data collection is not an easy job.
There must be some trained person/persons to do this job. Usually, the collected data are of two types.
Primary Data: The data are called primary if it is collected originally by some individual/ department/agency.
The primary data is free from any statistical operation/treatment. There are various methods to collect the
primary data. For example: personal interviews, indirect personal investigation, questionnaires, local sources,
enumerators.
Secondary Data: the data is called secondary when the primary data has been treated by some statistical tool.
If the primary data have been treated statistically it is no more primary. It becomes secondary data .The

6. secondary data are collected from individual units but are taken from different sources called secondary
sources. Some of these sources are :Official statistics, Semiofficial, Newspapers, and Trade Journals.
One or more of the following methods are employed to collect primary data:
i) Direct Personal Investigation.
ii) ii) Indirect Investigation.
iii) Collection through Questionnaires
iv) Collection through Enumerators
v) Collection through Local Sources
Application of Statistics in Pharmaceutical Sciences
Statistics course in this department is taught in the context of the development of new pharmaceutical and
biopharmaceutical products, with the goal of providing a solid knowledge and understanding of the nature, methods,
applications, and importance of the discipline of Statistics. It should be emphasized that we are not training our
students to be professional statisticians. Rather, we wish them to become familiar with the basics of design
,methodology ,and analysis as used in the development of new drugs. We aim to convey the following information:
1. why, and how, data are collected in clinical studies (to investigate a specific question, using appropriate study
design and research methodology)
2. how these data are summarized and analyzed (descriptive statistics, hypothesis testing and inferential
statistics, statistical significance)

7. 3. what the results mean in the context of the clinical research question (interpretation, estimation, and clinical
significance)
4. how the results are communicated to regulatory agencies and to the scientific and medical communities.