LECTURE 1
Introduction to Statistics
SP110 STATISTICS FOR PSYCHOLOGY

OUTLINE
What is Statistics?
Branches of Statistics
Population and Sample
Data and Variable
Types of Data and Variables
Parameter and Statistic
Levels of Measurement
Independent and Dependent Variables
Parametric and Non-Parametric Tests

WHAT IS STATISTICS?

Uses of Statistics
•
Organize and summarize information
•
Determine exactly what conclusions are justified based on
the results that were obtained
Goals of statistical procedures
•
Accurate and meaningful interpretation
•
Provide standardized evaluation procedures

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BRANCHES OF STATISTICS
There are two main branches of statistical methods
Descriptive statistics
•
Psychologists use descriptive statistics to summarize and describe a
group of numbers from a research study.
Inferential statistics
•
Psychologists use inferential statistics to draw conclusions and to make
inferences that are based on the numbers from a research study but
that go beyond the numbers.

POPULATION AND SAMPLE
Population
•
The set of all the individuals of interest in a particular study
•
Vary in size; often quite large
Sample
•
A set of individuals selected from a population
•
Usually intended to represent the population in a research
study

DATA AND VARIABLE
Data
•
Measurements or observations of a variable
Variable
•
Characteristic that can have different values

TABLE is aVARIABLE?

TABLE
is a
VARIABLE

SIZE OF A TABLE is aVARIABLE?

SIZE OF A TABLE
is a
VARIABLE

Types of Data
Types of Variables
•
Quantitative Data
•
Quantitative Variable
•
Discrete
•
Continuous
•
Qualitative Data
•
Qualitative Variable
TYPES OF DATA AND VARIABLES