Lecture18_ch8New

# Lecture18_ch8New - STAT 350 Lecture 18 8.5 Further Aspects...

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STAT 350 Lecture 18 8.5 Further Aspects of Hypothesis Testing

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Review Question The number of degrees of freedom for a paired t test, where the data consists of 10 independent pairs, is equal to 20 18 10 9 8
Topics Type I and Type II errors Statistical vs Practical Significance The Relationship Between Test Procedures and Confidence Intervals Lab 4 discussions

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Errors in Hypothesis Testing Type I Error: Rejecting H 0 when H 0 is actually true Type II Error: Not rejecting H 0 when H 0 is false
Type I Error Rejecting H 0 when H 0 is actually true The significance level α is the probability of making a type I error. If α =0.01, then there is 1% chance of making a type I error. If H0 is true and the test procedure is used repeatedly on different samples, H0 will be rejected (incorrectly) 1% of the time.

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Statistical vs. practical significance What is statistically significant? When the P-value is smaller than the chosen significant level α , it is customary to say that the result is statistically significant. When the result is statistically significant, the null hypothesis is rejected. Statistical vs practical significance Even after H0 has been rejected, the data may suggest that there is no practical difference.
Example 8.12

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## This note was uploaded on 04/23/2011 for the course STAT 350 taught by Professor Staff during the Spring '08 term at Purdue.

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Lecture18_ch8New - STAT 350 Lecture 18 8.5 Further Aspects...

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