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Unformatted text preview: Statistics for Economists Lecture 16 Kata Bognar UCLA Hypothesis Tests for the Population Mean PValue Approach Unknown σ Statistics for Economists Lecture 16 Kata Bognar UCLA May 27, 2010 Statistics for Economists Lecture 16 Kata Bognar UCLA Hypothesis Tests for the Population Mean PValue Approach Unknown σ Announcements • Homework 6 will be posted this afternoon. • Practice final will be posted over the weekend. Statistics for Economists Lecture 16 Kata Bognar UCLA Hypothesis Tests for the Population Mean PValue Approach Unknown σ Last Lecture • Hypothesis test for the population mean • zTest, critical value approach Statistics for Economists Lecture 16 Kata Bognar UCLA Hypothesis Tests for the Population Mean PValue Approach Unknown σ Today’s Outline 1 PValue approach, ttest 2 Inference for population proportion 3 Readings: Weiss, Chapter 9.5  9.6, 12.1  12.2 4 Readings for next class: Weiss, Chapter 14.1 Statistics for Economists Lecture 16 Kata Bognar UCLA Hypothesis Tests for the Population Mean PValue Approach Unknown σ PValue Approach • An alternative to the critical value approach of hypothesis testing. • The Pvalue gives the probability that the test statistic takes a value that is at least as extreme as the observed value. • Suppose that the observed value of the test statistic is z . • if the test is twotailed then the Pvalue = P (  Z  >  z  ) . • if the test is lefttailed then the Pvalue = P ( Z < z ) . • if the test is righttailed then the Pvalue = P ( Z > z ) . • The Pvalue is called the observed significance level or the probability value. Statistics for Economists Lecture 16 Kata Bognar UCLA Hypothesis Tests for the Population Mean PValue Approach Unknown σ PValue Approach  Example 1. A health club claims that their members lose on average more than 10 pounds within the first month after joining the club. To verify this statement one collects a random sample of 36 members of the club and finds that they lost on average 10.8 pounds within the first month. The weight losses in the population follow a normal distribution with a standard deviation known to be 2.4 pounds....
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 Spring '07
 Guggenberger
 Statistics, Normal Distribution, Standard Deviation, Statistical hypothesis testing, Kata Bognar UCLA

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