Chapter 7 Notes 7 1 Hypotheses Null Hypothesis

Chapter 7 Notes 7 -1: Hypotheses Null Hypothesis (H 0) – ALWAYS contains an element of equality (Either ≥, ≤, or =) Alternate Hypothesis (Ha) – ALWAYS strictly inequality (Either <, >, ≠) The alternate hypothesis is the COMPLEMENT of the null hypothesis. If H 0 is ≥, then Ha is <. If Ha is <, it is called a “left-tail test” If H 0 is ≤, then Ha is >. If Ha is >, it is called a “right-tail test” If H 0 is =, then Ha is ≠. If Ha is ≠, it is called a “two-tail test” Either one of these hypotheses may be the claim – you have to read the question/statement to determine which one represents the claim. We ALWAYS test the NULL hypothesis (Reject or Fail to Reject)

Chapter 7 Notes 7 -1: Hypotheses Types of Errors Type I – Reject the null hypothesis when it was actually true (False negative) Type II – Fail to reject the null hypothesis when it is false (False positive)

Chapter 7 Notes Hypotheses Steps for Hypothesis Testing You can not use a hypothesis test to support your claim if your claim is the null hypothesis. If you want a conclusion that supports your claim, word your claim so that it is the alternate hypothesis. If you want to reject a claim, word it so it is the null hypothesis.

Chapter 7 Notes Hypotheses Example 5 (Page 374) A medical research team is investigating the benefits of a new surgical treatment. One of the claims is that the mean recovery time for patients after the new treatment is less than 96 hours. How would you write the null and alternate hypotheses if (1) you are on the research team and want to support the claim? (2) you are on an opposing team and want to reject the claim? 1) Because you want to support this claim, make the claim the alternate hypothesis. 2) Because you want to reject this claim, make the claim the null hypothesis.

Assignments: Classwork: Page 375 #1 -22 All Homework: Pages 376 -377 # 23 -49 Odds