Statistics

Lecture by S.Imran

What is research?

• To study a phenomenon/problem/issue comprehensively to find its solution.

• For example– Fear– Dengue– Terrorism

What is Science?

• Who are the Scientists?– People with white-coat working in laboratories,

doing different kinds of experiments? – Cut-off from the society?– Always discovering or inventing new things like

atom bomb, germs, virus, etc.• This notion is completely wrong

What is Science?

• People who study phenomenon/ problem/issue systematically to find its solution are called scientists

• So science is basically a systematic inquiry of problems/issues/phenomenon

Scientific Research?

• Systematic, controlled, empirical and critical investigation of phenomenon guided by some theory or hypothesis.

• Book to consult: Mass Media Research: An Introduction by Wimmer and Dominick

Aim of Scientific Research

– Is scientific research (systematic inquiry of problem) aimed for the betterment of the society or else?

– Answer is: A big “NO”

– Than why a scientific research is conducted?

Aim of Scientific Research?

• The aim of Scientific research is theory

Theory

Generation Verification

What is Theory?

• Theory is a logic– What is logic?• Relationship between two or more things/ideas

/concepts• For example• Hard working ------------ Academic Grades• Food --------- Health• Gun -------- Fear

Theory

• Scientifically this relationship is called proposition.

• A Theory can comprise a single or set of propositions

Theory

• So a scientific research is basically aimed to EITHER– generate such relationships among different

concepts/constructsOR– verify such relationships among different concepts

On the basis of this

• We can categorize a scientific research into two categories

• 1. Theory Generation approach (Inductive or Qualitative )

• 2. Theory Verification approach (Deductive or Quantitative)

Steps of Scientific Research

1. Selection of Problem/issue2. Study Previous research about the selected

topic and Logic/theory ( Called Literature Review)

3. Formulation of Hypotheses/ Research Question

• Hypotheses for Quantitative Research• Research Question for Qualitative Research

Steps of Scientific Research

4. Selection of Research Methodology5. Data Collection6. Data Analysis & Findings7. Conclusion

Theory verified or not?what new theory created?

Point to Remember

• Applying Statistics is part of quantitative Research

What is statistics?

• Statistics is the science of conducting studies to• collect,• organize, Descriptive • summarize, • analyze, and • draw conclusions Inferential

from data.In simple words

Statistics is to

Collect data

Describe dataDraw inferences from data

What is data?

• Anything (names or numerals) we collect is data• if names than string data• If numerals than numeric data• From Whom?– Population – Sampling Frame– Sample– Sampling Techniques

• Probability Technique• Non-probability Techniques

• Nature of data• Levels of data / measurement– Nominal Qualitative data (attributes)– Ordinal– Interval Quantitative data (numbers)– Ratio

1. Data Collection• From Whom?

– Population – Sampling Frame– Sample– Sampling Techniques

• Probability Technique• Non-probability Techniques

• How?By using some tool/ Instrument– In Media studies tools can be

• Questionnaire Surveys• Interview Schedule

• Code sheets Content analysis

Tools

• Tools comprises of Variables,• What is a variable?

• A characteristics that can vary among individuals

– Uni-dimensional• Can be directly observed/measured e.g age, gender,

class,

– Multi-dimensional• They cannot be measured directly e.g achievement,

intelligence, participation, involvement

Multi-dimensional concepts and construct

Concepts• Abstract idea about some thing, formed by generalization.• e.g.

Construct• ,abstraction with some added meanings• e.g.• If they cannot be measured directly, than how we measure them?• The answer is “ through scales”

• What are scales?

– Kinds• IV• DV• Moderating• Mediating• Confounding/Extraneous

• How to measure variables?– Direct measurement (For uni-dimensional)– Indirect Measurement (For multi-dimensional)• By using scales or indexes• What is a scale?

– Scales used in Media studies» Likert Scale» Semantic differential Scale

Flow Chart

Description (Descriptive Statistics)

Descriptive statistics consists of the collection, organization, summarization, and presentation of data.

Descriptive Statistics

Types of descriptive statistics:• Organize Data– Tables• Frequency Distributions• Percentages

– Graphs• Bar Chart or Histogram• Frequency Polygon• Frequency Curve• Pi chart

Descriptive Statistics

Data Distribution Summary StatisticsTables Graphs Measure of Measure of1.Frequency 1. Bar Chart/Histogram Central Tendency Dispersion2. Percentage 2. Pi Chart 1. Mean 1. Range

3. Frequency Polygon 2. Mode 2. Variance4. Frequency Curve 3. Median 3. Standard

Deviation Normal Non-Normal outliers Skewness Kurtosis

Tables

• No. of hour People Watch TV in a day3, 5, 3, 2, 7, 4, 3, 5, 1, 6,

Hours Frequency (f) Percentage (%)1 1 10%

2 1 10%

3 3 30%

4 1 10%

5 2 20%

6 1 10%

7 1 10%

GraphsBar Chart/Histogram

Polygon

Pi chart

Measure of Central Tendency

• What is the center of data?

• Mean Mode Median• Mathematical Average Most occurring value Position average• Sum of all value value with highest frequency physically

middle• no. of values• Sensitive to outlier does not affect with

outlier• Data is interval or ratio nominal interval or ordinal

Data Distribution

• Symmetric Cure

Properties of mean and median

• For symmetric distributions, mean = median• For skewed distributions, mean is drawn in

direction of longer tail, relative to median• Mean valid for interval scales, median for

interval or ordinal scales• Mean sensitive to “outliers” (median often

preferred for highly skewed distributions)• When distribution symmetric or mildly skewed

or discrete with few values, mean preferred because uses numerical values of observations

3. Draw Inferences (Inferential Statistics)

• Inferential statistics consists of generalizing from samples to populations, performing estimations and hypothesis tests, determining relationships among variables, and making predictions.

Hypothesis

• What is a Hypothesis?• Kinds of hypothesis– Null– AlternativeDimensions of Hypothesis

Directional (one tailed)Non-directional (2 tailed)

What is Probability Level (p)?