unit 4 lesson 1
TRANSCRIPT
University of North Texas Dr. J. Kyle Roberts © 2004
Unit 4: Statistical Significance
Lesson 1: Constructing Confidence Intervals
EDER 6010: Statistics for Educational Research
Dr. J. Kyle Roberts
University of North Texas
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University of North Texas Dr. J. Kyle Roberts © 2004
Mean DifferencesIQ Scores
100 11585
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University of North Texas Dr. J. Kyle Roberts © 2004
Standard Error of the Mean
n
SDXX
SEMX Sample of IQ ScoresMean = 100SD = 15N = 25
325
15
QI
QI
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University of North Texas Dr. J. Kyle Roberts © 2004
Critical Values
-1.96 SD +1.96 SD
95% Confidence Intervals
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University of North Texas Dr. J. Kyle Roberts © 2004
Computing the CI95%
))((%95 XcvzXCI Sample of IQ ScoresMean = 100SD = 15N = 25
3QI
CI95% = 100 ± (1.96)(3)CI95% = 100 ± 5.88-or-CI95%: 105.88 – 94.12
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University of North Texas Dr. J. Kyle Roberts © 2004
What Does a CI Tell Me?CI95% = 100 ± 5.88
1. We are 95% confident that the interval around our obtained mean contains the population mean.
2. If we continued to sample from the population an infinite number of times, 95% of those sample means and confidence intervals would capture the population mean.
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University of North Texas Dr. J. Kyle Roberts © 2004
Confidence Intervals from a Population
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University of North Texas Dr. J. Kyle Roberts © 2004
Unit 4: Statistical Significance
Lesson 1: Constructing Confidence Intervals
EDER 6010: Statistics for Educational Research
Dr. J. Kyle Roberts
University of North Texas