Copyright 2011 Pearson Education, Inc.Slide 5-*Unit 5AFundamentals of StatisticsPage 286

Learning ObjectivesStudents will demonstrate the ability to:Identify the population, sample, sampling method, topic, and variables in a statistical studyIdentify potential sources of bias in a statistical studyDescribe and recognize whether a study is not blind, single-blind, or double-blindIdentify whether a study is observational or experimentalCalculate the confidence interval of a sample statistic given the margin of errorUse confidence intervals to determine whether a survey result is statistically significant

Copyright 2011 Pearson Education, Inc.Slide 5-*

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Example: Identifying Data SetsIn a recent survey, 1708 adults in the United States were asked if they think global warming is a problem that requires immediate government action. Nine hundred thirty-nine of the adults said yes. Identify the population and the sample. (Adapted from: Pew Research Center)*Larson/Farber 4th ed.

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Solution: Identifying Data SetsThe population consists of the responses of all adults in the U.S.The sample consists of the responses of the 1708 adults in the U.S. in the survey.The sample is a subset of the responses of all adults in the U.S.

*Larson/Farber 4th ed.

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Example: Distinguish Parameter and StatisticDecide whether the numerical value describes a population parameter or a sample statistic.A recent survey of a sample of MBAs reported that the average salary for an MBA is more than $82,000. (Source: The Wall Street Journal)Solution:Sample statistic (the average of $82,000 is based on a subset of the population)*Larson/Farber 4th ed.

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Example: Distinguish Parameter and StatisticDecide whether the numerical value describes a population parameter or a sample statistic.Starting salaries for the 667 MBA graduates from the University of Chicago Graduate School of Business increased 8.5% from the previous year.Solution:Population parameter (the percent increase of 8.5% is based on all 667 graduates starting salaries)*Larson/Farber 4th ed.

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Copyright 2011 Pearson Education, Inc.Slide 5-*You are conducting a survey of students in a dormitory. You choose your sample by knocking on the door of every fifth room.

To survey opinions on a proposed new water line, a research firm randomly draws the addresses of 200 homeowners from a public list of all homeowners.

Identify the Sampling Method Used

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Page 298 Identify the Sampling MethodCopyright 2011 Pearson Education, Inc.Slide 5-*

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How confident are we?Unless we are told otherwise, assume that the margin of error is defined to give us 95% confidence that the confidence interval contains the population parameter.

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Example 6 Close ElectionPage 296Copyright 2011 Pearson Education, Inc.Slide 5-*

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