Transcript PY 603 – Advanced Statistics II

PY 603 – Advanced Statistics II
TR 12:30-1:45pm
232 Gordon Palmer Hall
Jamie DeCoster
Introduction to Regression
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Travel survey
Syllabus
Prerequisites (PY 602 topics)
Describing a data set
Steps to perform a hypothesis test
Hypothesis tests of a point estimate
Prerequisites (PY 602 topics)
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Knowledge of ANOVA
Knowledge of SPSS
Knowledge of Excel
Knowledge of Word – equation editor
Describing a Data Set
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Data source vs. data set
Cases
Variables
Unit of analysis
Numeric vs. categorical variables
Steps to Describe a Data Set
• Provide a general description of the data
set
• Describe the subject population
• Report the unit of analysis for the data set
• Name your variables
• Describe what the variable measures
• State the units of numeric variables or the
groups for categorical variables
Steps to Perform a Hypothesis
Test
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Determine null and alternative hypotheses
Select a sample
Collect data discriminating the hypotheses
Compute a test statistic
Determine the probability of getting the
observed statistic if the null was true
• State whether you reject or fail to reject
the null hypothesis
Hypothesis Test of a Point
Estimate
• Tests whether an estimated value is
significantly different from a constant
• Commonly performed in regression
– Values of estimates
– Slopes of regression lines
• General form
estimate  null value
t
standard error of the estimate
Reporting a Hypothesis Test of a
Point Estimate
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State the null and alternative hypotheses
Report the estimate
Report the standard error of the estimate
Report the df associated with the standard
error
• Calculate the t statistic
• Report the p-value for the t
• State your conclusion