# STAT 4101 LECTURE ONE

```Basic Issues in Statistics
School of Statistics
June 10, 2019
Outlines
• Definition of Statistics
• How Statistics Helps Us Learn about the
World
-Practical Questions
-Its Importance, essentials and Procedure
• Theory and Reality
What is Statistics?
• Statistics is the art and science of designing
studies and analyzing the data that those
studies produce.
• Its ultimate goal is translating data into
knowledge and understanding of the world
around us.
• In short, statistics is the art and science of
learning from data .
Practical Questions
• How can you evaluate evidence about global
warming?
• Are cell phones dangerous to your health?
• What’s the chance your tax return will be audited?
• How likely are you to win the lottery?
• Is there bias against women in appointing
managers?
• How can you analyze whether a diet really works?
• How can you predict the selling price of a house?
Importance
• Making Conclusions in Medical Research
Studies
• Predicting an Election Using an Exit Poll
• Consumers are sampled to provide
information for predicting product
preferences.
• Using a Survey to Investigate People’s
Beliefs
Importance
• controlled environmental conditions on
humans in order to infer the appropriate
treatment for various illnesses.
• Engineers sample a product quality
characteristic and various
Decision Under Uncertainty
• You’ll face financial decisions such as
choosing between an investment with a sure
return and one that could make you more
money but could possibly cost you your entire
investment.
Statistics Essentials
• You’ll learn how to analyze the available
in such scenarios.
• Understanding of statistics is essential for
making good decisions in an uncertain
world
Statistical Procedure
• Statistical methods help us investigate
questions in an objective manner.
(1)formulate a statistical question
(2)collect data
(3) analyze data
(4) interpret results
• Why is probability relevant to inferential
statistics? Statistics are, in one sense, all
deal with establishing whether differences
or associations exist between sets of data.
The data comes from the sample we use,
and the sample is taken from a population.
• Suppose that two candidates are running for a
public office in our community and that we
wish to determine whether our candidate,
Jones, is favored to win. The population of
interest is the set of responses from all
eligible voters who will vote on election day,
and we wish to determine whether the fraction
favoring Jones exceeds .5.
Elements of Science
• 1. Reality: the real-world as it exists
independently of human knowledge;
• 2. Theory: coherent sets of ideas about how
some portion of reality works;
• 3. Data: observations and measurements on
some real-world system;
• 4. Models: abstract, but rigorous and specific,
representations of reality, based on theory or
data or both
Theory and Reality
• Theory: A collection of propositions to
illustrate the principles of a subject.
• In modern science, the term &quot;theory&quot;
refers to scientific theories, a wellconfirmed type of explanation of nature,
made in a way consistent with scientific
method, and fulfilling the criteria required
by modern science.
• Scientific theories are the most reliable,
rigorous, and comprehensive form of
scientific knowledge.
• Theories are analytical tools
for understanding, explaining, and
making predictions about a given subject
matter.
Illustrative Example
• For each of the following situations,
identify the population of interest, the
inferential objective, and how you might go
(1) A university researcher wants to estimate
the proportion of U.S. citizens from
“Generation X” who are interested in starting