This document provides an overview of key concepts in statistics including collecting and presenting data, variables, populations and samples, descriptive and inferential statistics, and sampling concepts. It gives examples of types of variables and data sources. The example given is a survey of over 17,000 web users to determine what percentage are addicted to the internet, with the findings showing 5.7% met the criteria for addiction.

1. FUNDAMENTALS OF
STATISTICS

2. STATISTICS
• Collect data
• Present data
• Characterize
data
Data
Analysis
Decision
making

3. FIVE WORDS OF STATISTICS
Population
Sample
Variable
Parameter
Statistic

4. EXAMPLE

5. TYPES OF VARIABLES

6. BRANCHES OF STATISTICS
Descriptive Statistics – organizing, summarizing and
displaying data
• Describes important characteristics of data e.g. tables, charts,
averages, percentages
Inferential Statistics – using sample data to draw
conclusions or make inferences about an entire
population

7. DATA SOURCES
Primary data sources
Secondary data sources
• Surveys
• Interviews
• Experiments
• Observations

8. EXAMPLE
What percentage of web users are addicted to
internet? To find out, a psychologist designed a
series of 10 questions based on a widely used
set of criteria for gambling addiction and
distributed them through the Web site ,
ABCNews.com (A sample question: Do you use
the Internet to escape problems?). A total of
17251 web users responded to the
questionnaire. If participants answered “Yes” to
at least half of the questions, they were viewed
as addicted. The findings, released at the 1999
annual meeting of the American Pshychological
Association, revealed that 990 respondents, or
5.7% are addicted to the Internet.

9. Identify the data collection method.
Identify the target population.
Are the sample data representative of the population?

10. SAMPLING CONCEPTS
Frame
Sampling
• Probability sampling
• Simple random sampling
• Stratified sampling
• Systematic sampling
• Cluster sampling
• Convenience sampling