4-16-10 Chapter 10 Agenda Quiz Announcements Project 2 Chapter 9 Chapter 10 Quiz 3: 61 Section 1. 12.10 to 12.20 2. 39.42 to 61.58 3. N=461 Quiz 3: Section 61, Question 4 1. Ho: µ > 26 Ha: µ < 26 2. Reject Ho if -Zcalc < -Zcrit or if p alpha(.01) (Zcalc) -2.25 > (Zcrit) -2.33 We do not have statistically significant evidence at the 1% level to prove that the social scientist is right. Quiz 3: Section 62 1. 12.10 to 12.20 2. 41.41 to 59.59 3. N=166 Quiz 3: Section 62, Question 4 1. Ho: µ = 80 Ha: µ ? 80 2. Reject Ho if -Zcalc < -Zcrit or Zcalc > Zcrit or if p alpha(.05) (-Zcalc) -1 > (-Zcrit) -1.96 We do not have statistically significant evidence at the 5% level to prove that the population mean does not equal 80. Announcements Quiz over chapter 10 & 12 next Friday, April 23rd Project turn in and Review on Friday, April 30th Homework due Monday, May 3rd FINAL, May 5th Improvements?more cookies ? Well - Explaining chapters Responding to emails Website - More practice problems Update it more efficiently Quiz - Study guides Write more of what we did wrong Recitation - More examples New material/calculations Slow down Homework - Go over complicated ?s Review Session & PowerPoint Project - Explain more before its due Project Http://www.Amazon.com NO CHEATING!!!! Chapter 10 material Explanation Pvalue --------Zcalculated/ Tcalculated Alpha------------Zcritical/ Tcritical Chapter 9- Example 1 ?Currently, 80% of Americans wear their seat-belt,? stated a senator in his campaign speech. ?Elect me and you?ll see an increase in people utilizing their seat-belts.? Today, a random sample of 500 Americans showed that 415 consistently wear their seat-belts. Can we conclude at the 10% significance level that he is right? Answer 1. Ho: ? <.80 Ha: ? > .80 2. Reject Ho if pvalue < alpha (.10) or Zcalc> Zcrit (1.28) 3. Zcalc= Zcalc= 1.677 4. Reject Ho because pvalue (.0465) < alpha (.10) And Zcalc (1.677) > Zcrit (1.28) Chapter 9- Example 2 The owner of a restaurant has surveyed a random sample of 300 customers. He would like to determine whether the mean age of his customers is over 40. If so, he plans to alter the meals to appeal to a older crowd. If not, there will be no changes in the meals. Within the sample, suppose he found that the mean was 40.5 years and the standard deviation was 3 years. Is there a significant increase at the 5% level? Answer 1. Ho: µ < 40 Ha: µ > 40 2. Reject Ho if pvalue < alpha (.05) or Tcalc> Tcrit (1.660) 3. Tcalc= Tcalc= 2.89 4. Reject Ho because (.001 Tcrit (1.660) Chapter 10 Chapter 9 Hypothesis testing for 1 sample Chapter 10 Hypothesis testing for 2 samples Remember, same 4 step process Comparing Two Proportions 1. State the Hypotheses H0: ?a = ? b ; ?a > ?b ; ?a < ?b H1: ?a ? ?b ; ?a < ?b ; ? a> ?b 2. State the Decision Rule Reject H0 if Pvalue < alpha |Z calculated| >|Z critical| 3. Zcalculated= 4. Make the Decision Chapter 10- Example 1 How many full page advertisements are found in a magazine? In an October issue of Muscle and Fitness there were 252 ads of which 97 were full page. For the same month, the magazine Glamour had 342 ads, of which 167 were full page. Is the difference significant at an alpha = .01? Means or proportions? Chapter 10- Example 1 How many full page advertisements are found in a magazine? In an October issue of Muscle and Fitness there were 252 ads of which 97 were full page. For the same month, the magazine Glamour had 342 ads, of which 167 were full page. Is the difference significant at an alpha = .01? Process 1. State the Hypotheses H0: ?m = ?g H1: ?m ? ?g 2. State the Decision Rule Reject H0 if p < alpha(.01) Z calc >Zcrit (2.575) or -Zcalc< -Zcrit (-2.575) 3. Zcalc= -2.51, Pvalue=.0060(2)= .012 4. Fail to reject Ho. There is not statistically significant evidence at 1% level to prove a difference in proportions -2.51(Zcalc) > -2.575(-Zcrit) & .012(Pvalue)> .01(alpha)
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