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MGMT 276: Statistical Inference in Management. Extra Credit Opportunity. Learn more about how business research is actually conducted . Requires two online surveys In-class on November 10 th is dedicated to this topic.
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MGMT 276: Statistical Inference in Management Extra Credit Opportunity • Learn more about how business research • is actually conducted. • Requires two online surveys • In-class on November 10th is dedicated to this topic http://www.thedailyshow.com/video/index.jhtml?videoId=188474&title=an-arab-family-man
Extra Credit Opportunity • - participate in study • There are 3 parts: • Part 1: Simply complete an online questionnaire by Oct 17th • Part 2: Simply complete a 2nd online questionnaire by Oct 24th (These will be spaced approx 2 weeks apart) • Part 3: In-class activity on Nov 10th • (Bring laptop to class) • To sign up - register http://mgmt.participantpool.com • (You should have received an email describing this in more detail) http://www.youtube.com/watch?feature=player_embedded&v=yfRVCaA5o18
Please click in Set your clicker to channel 03 My last name starts with a letter somewhere between A. A – D B. E – L C. M – R D. S – Z Please double check – Allcell phones other electronic devices are turned off and stowed away • No Homework • Just study for exam http://www.youtube.com/watch?feature=player_embedded&v=yfRVCaA5o18
MGMT 276: Statistical Inference in Management Welcome http://www.thedailyshow.com/video/index.jhtml?videoId=188474&title=an-arab-family-man
Use this as your study guide By the end of lecture today10/11/11 One-tailed versus Two-tailed test Type I vs Type II Error
Please read: Chapters 5 - 10 in Lind book & Chapters 10, 11, 12 & 14 in Plous book: Lind Chapter 5: Survey of Probability Concepts Chapter 6: Discrete Probability Distributions Chapter 7: Continuous Probability Distributions Chapter 8: Sampling Methods and CLT Chapter 9: Estimation and Confidence Interval Chapter 10: One sample Tests of Hypothesis Plous Chapter 10: The Representativeness Heuristic Chapter 11: The Availability Heuristic Chapter 12: Probability and Risk Chapter 14: The Perception of Randomness
Exam 2 – Thursday (10/13/11) Study guide is online Bring 2 calculators (remember only simple calculators,we can’t use calculators with programming functions) Bring 2 pencils (with good erasers) Bring ID
Why do we care about the z scores that define the middle 95% of the curve?Inferential Statistics Hypothesis testing with z scores allows us to make inferences about whether the sample mean is consistent with the known population mean.
Measurements that occur within the middle part of the curve are ordinary (typical) and probably belong there 95th Percentile: 95% of the distribution falls below (or is equal to) that score 5th Percentile: 5% of the distribution falls below (or is equal to) that score Distribution of the weights of healthy babies Moving from descriptive stats into inferential stats…. 90% 5% 5% Measurements that occur outside this middle ranges are suspicious, may be an error or belong elsewhere What percent of the distribution will fall above that score? What percent of the distribution will fall below that score? http://today.msnbc.msn.com/id/33411196/ns/today-today_health/ http://www.youtube.com/watch?v=0r7NXEWpheg
Possible outcomes of hypothesis test Status of Null Hypothesis(actually, via magic truth-line) True Ho False Ho Do notReject Ho Decision madeby experimenter Reject Ho You are wrong! Type II error(miss) You are right! Correct decision You are wrong! Type I error(false alarm) You are right! Correct decision • Probability of rejecting a true null hypothesis = alpha • The alpha you choose becomes the probability of • making a Type I error
One versus two tail test of significance:Comparing different critical scores(but same alpha level – e.g. alpha = 5%) One versus two tailed test of significance 95% 95% 2.5% 5% 2.5% How would the critical z change? Pros and cons…
One versus two tail test of significance5% versus 1% alpha levels How would the critical z change? 2.5% .5% 5% 2.5% 1% .5% -1.64 or +1.64 -1.96 or +1.96 -2.33 or +2.33 -2.58 or +2.58
One versus two tail test of significance5% versus 1% alpha levels What if our observed z = 2.0? How would the critical z change? -1.64 or +1.64 -1.96 or +1.96 Remember, reject the null if the observed z is bigger than the critical z Reject the null Reject the null -2.33 or +2.33 -2.58 or +2.58 Do notReject the null Do notReject the null
One versus two tail test of significance5% versus 1% alpha levels What if our observed z = 1.75? How would the critical z change? -1.64 or +1.64 -1.96 or +1.96 Do not Reject the null Remember, reject the null if the observed z is bigger than the critical z Reject the null -2.33 or +2.33 -2.58 or +2.58 Do notReject the null Do notReject the null
One versus two tail test of significance5% versus 1% alpha levels What if our observed z = 2.45? How would the critical z change? -1.64 or +1.64 -1.96 or +1.96 Remember, reject the null if the observed z is bigger than the critical z Reject the null Reject the null -2.33 or +2.33 -2.58 or +2.58 Do notReject the null Reject the null
Review for Exam 2 http://www.thedailyshow.com/video/index.jhtml?videoId=188474&title=an-arab-family-man
Thank you! See you next time!!