Important Terms
Major Branches of Statistics
1. Descriptive Statistics
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Organizing, Summarizing Information
Graphical techniques
Numerical techniques
2. Inferential Statistics
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Estimation
Decision making
© 2008 Brooks/Cole, a division of Thomson Learning, Inc.
Important Terms
Sample – A sample is a subset of the
population, selected for study in some
prescribed manner.
Using sample data rather than population data
is
– more practical than a census.
– Gives variable results with some possibility of
a wrong conclusion being adopted.
© 2008 Brooks/Cole, a division of Thomson Learning, Inc.
Practice Problem
The financial aid officers of a university wish
to estimate the average amount of money
that students spend on textbooks each term.
They select 150 students and ask them the
amount spent on book. Describe the
population and sample for this problem.
Population – The entire collection of
individuals or objects about which
information is desired is called the population.
Collection of data from every member of the
population is called a census,
– allows a question about the population to be
definitively answered.
– may be expensive, impractical, or sometimes
impossible.
© 2008 Brooks/Cole, a division of Thomson Learning, Inc.
Practice Problem
Mr. Holland wants to get the opinions of
graduating seniors from last year (412
students). He sends a survey to 100 of the
graduating seniors, and 43 reply. Identify
the population and sample.