MKF2121 Week 08.pdf - Lecture 8 Logic of Hypothesis Testing Cross-Tabulation Dr Junzhao Ma MKF2121 1 Marketing Research Methods Todays agenda More on

MKF2121 Week 08.pdf - Lecture 8 Logic of Hypothesis Testing...

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1Lecture 8Logic of Hypothesis TestingCross-TabulationDepartment of MarketingDr. Junzhao MaMKF2121Marketing Research Methods1Today’s agenda2More on hypothesis testing – the intuition behind statistical tests and the concept of a test statisticLearn about one type of tests of association: cross-tabulation (Chi-square test)Last week we discussed the steps of hypothesis testing1. Problem Definition (RQ)2. Clearly State the Null and Alternative Hypotheses3. Choose the relevant statistical test4. Calculate p-value5. Is p-value<0.05?NoDo not reject nullReject null hypothesisYes3
24Revisit - why do we have to use statistical tests to “answer” RQ?Sample characteristics population characteristicsPopulation characteristics is unknownThink like a detective: what does the evidence (sample characteristics) tell me what really happened (population characteristics)?Hypothesis testing: the formal process to use the statistical properties of the data to evaluate beliefs about population characteristics (hypothesis)Population?SampleStatistical testing - three levels of understandingMechanical – know which button to push in SPSS, what to look for in the outputMathematical (formula) – nice to have (in the textbook), but not requiredConceptual – the intuition behind the technique used5Example to illustrate the rationale behind the statistical testing (in particular, test statistic)Buyer IDMiles per gallon130.9224.5331.2428.7535.1629728.8823.19311030.21128.41229.31324.214271526.716311723.51829.41926.32027.52128.2Toyota dealership in the city of New Haven claims that the average miles per gallon (MPG) is 30 for the new Toyota CorollaA local consumer group collected data from the recent buyers to verify this claimRQ – Is the new Toyota Corolla’s average MPG equal to 30?
3Step 2: Hypothesis formulationH0 (Null): Miles per gallon = 30 milesIn words: the new Toyota Corolla’s average MPG is 30H1 (Alternative): Miles per gallon 30 milesThe new Toyota Corolla’s average MPG is not 307The mechanics: steps needed for hypothesis testing8Step 3 – pick a testHypothesisTestingTest of Association(relational RQ)Test of Differences(comparative RQ)MeansProportionsDifferent forms of t testCross tabulationCorrelationMultiple regressionStep 4&5 : Execute the test and compare p-value9One-Sample Statistics2528.17203.0339.6068MPGNMeanStd. DeviationStd. ErrorMeanOne-Sample Test-3.01324.006-1.8280-3.0803-.5757MPGtdfSig. (2-tailed)MeanDifferenceLowerUpper95% ConfidenceInterval of theDifferenceTest Value = 30P-value = 0.006 < 0.05, therefore we reject null hypothesis Conclusion: Reject the null hypothesis (i.e., the average MPG is not equal to 30)