COMM 207 Lecture Notes - Lecture 2: Type I And Type Ii Errors, Null Hypothesis, Test Statistic
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Summary of types of hypotheses: one-sided, greater than alternative. H0: m0 vs: one-sided, less than alternative. Ha : < m0: two-sided, not equal to alternative. H0 : = m0 vs. ha : m0: m0 is a given constant value (with the appropriate units) that is a comparative value. Or: reject h0, a weaker statement than accepting ha . In order to test h0 vs. ha, use the test statistic x z. If the population is normal or n is large*, the test statistic z follows a normal distribution. Steps in testing a greater than alternative in trash bag case #1: state the null and alternative hypotheses. Ha: > 25: specify the significance level . Ha: > 25 at the 0. 05 significance level: interpret the statistical results, conclude mean breaking strength of new bag exceeds 25 kg. Effect of : at = 0. 01, the rejection point is z0. 01 = 2. 33. Interpreting the weight of evidence against the null hypothesis:
