Scientific PapersAnnouncementsMicrosoft OfficeLab ReportsKey PartsIntroductionHypothesisNull HypothesisHypothesis TestingSlide 10Slide 11Statistical Tests and ProbabilityT-TestT-ValuesHypotheses for current studyUse of TestsHypothesesMethodsResultsDiscussionTables and FiguresCaptionsExampleLiterature CitedAbstractTitle PagePutting it all togetherScientific Paper AssignmentScientific PapersScientific PapersNew model for lab reportsNew model for lab reportsAnnouncementsAnnouncementsClass Book Debate – Tuesday night, Class Book Debate – Tuesday night, 7:30 PM, C-106 Holmes7:30 PM, C-106 HolmesMicrosoft OfficeMicrosoft OfficeMSU Computer StoreMSU Computer StoreOffice 2003 PRO WIN, MEDIA Office 2003 PRO WIN, MEDIA &LICENSE, ACADEMIC STUDENT &LICENSE, ACADEMIC STUDENT SELECTSELECT$60.00$60.00Lab ReportsLab ReportsLab Reports are similar to what scientists Lab Reports are similar to what scientists publish in research journalspublish in research journalsFollow format of scientific papersFollow format of scientific papersKey PartsKey PartsIntroductionIntroductionMethodsMethodsResultsResultsDiscussionDiscussionTables and FiguresTables and FiguresLiterature CitedLiterature CitedAbstractAbstractIntroductionIntroductionDescription of the general question and Description of the general question and backgroundbackgroundDescription of current project’s scope Description of current project’s scope and general methodsand general methodsHypothesis / hypotheses and predictionsHypothesis / hypotheses and predictionsHypothesisHypothesisPlural is hypothesesPlural is hypothesesTested and supported, not proved!Tested and supported, not proved!I tested the hypothesis that smaller computer I tested the hypothesis that smaller computer monitors are harder to use. monitors are harder to use. I tested the hypothesis that smaller computer I tested the hypothesis that smaller computer monitors are harder to use by comparing monitors are harder to use by comparing readability tests on a 15 inch and 17 inch readability tests on a 15 inch and 17 inch monitor.monitor.Null HypothesisNull HypothesisStates that there is no difference (between observed and States that there is no difference (between observed and expected, if there had been no effect)expected, if there had been no effect)HH00: "There will be no difference in readability between 15" : "There will be no difference in readability between 15" and 17" monitors."and 17" monitors."HH00: "There will be no relationship between processor : "There will be no relationship between processor speed and startup time, indicated by a line with a slope of speed and startup time, indicated by a line with a slope of 0."0."DO NOT INCLUDE NULL HYPOTHESIS IN PAPERDO NOT INCLUDE NULL HYPOTHESIS IN PAPERHypothesis TestingHypothesis TestingStatistical Tests are how scientists decide Statistical Tests are how scientists decide if data support their hypothesis if data support their hypothesis (NOT PROVE their hypothesis)(NOT PROVE their hypothesis)Four major statistical tests: T-test, X2 Four major statistical tests: T-test, X2 Test, Regression, ANOVATest, Regression, ANOVAHypothesisHypothesisProcessor speed has an effect on the Processor speed has an effect on the performance of the computer.performance of the computer.Null HypothesisNull HypothesisHH00: Processor speed has NO EFFECT on : Processor speed has NO EFFECT on the performance of a computer.the performance of a computer.Hypothesis TestingHypothesis TestingHypothesis testing is using statistical Hypothesis testing is using statistical values to determine whether the Null values to determine whether the Null Hypothesis is correctHypothesis is correctCommon Statistical Tests for Common Statistical Tests for Hypotheses: Hypotheses: tt-Test, ANOVA, Regression, -Test, ANOVA, Regression, XX22 (Chi – Square) (Chi – Square)Statistical Tests and Statistical Tests and ProbabilityProbabilityStatistical tests give a valueStatistical tests give a valueThat value can be related to a probabilityThat value can be related to a probabilityProbability is likelihood that NULL Probability is likelihood that NULL hypothesis is correct given the data you hypothesis is correct given the data you havehaveIf P < 0.05 (1/20), then you conclude If P < 0.05 (1/20), then you conclude NULL hypothesis is FALSENULL hypothesis is FALSET-TestT-TestCompares differences between two meansCompares differences between two meansFormula: T = (xFormula: T = (x11-x-x22)/SEM)/SEMSEM is Standard Error of Mean [SD/(N-1)]SEM is Standard Error of Mean [SD/(N-1)]T Values: Difference between mean in T Values: Difference between mean in comparison to the amount of spread in comparison to the amount of spread in your datayour dataT-ValuesT-ValuesIf T > 2.5 or 3.0, difference is usually If T > 2.5 or 3.0, difference is usually significant (this depends on your sample significant (this depends on your sample sizes)sizes)Hypotheses for current Hypotheses for current studystudyWhat were we testing?What were we testing?How did certain characteristics affect How did certain characteristics affect computer performance.computer performance.Use of TestsUse of Teststt-Test: Comparing two means-Test: Comparing two meansANOVA: Comparing multiple meansANOVA: Comparing multiple meansRegression: Looking for a slope in lineRegression: Looking for a slope in lineChi-Square: Looking at distribution Chi-Square: Looking at distribution patternspatternsHypothesesHypothesesThe startup speed of a computer is The startup speed of a computer is determined by processor speed. determined by processor speed. The startup speed of a computer is The startup speed of a computer is determined by the amount of RAM. determined by the amount of RAM. The stability of a computer is affected by The stability of a computer is affected by its operating system. its operating system.MethodsMethodsExplain what steps were taken in Explain what steps were taken in collecting data and whycollecting data and whyUse past tenseUse past tenseUse active voiceUse active voice““I entered data into a form,” not “The data I entered data into a form,” not “The data were entered into a form.”were entered into a form.”ResultsResultsPresent general trends without comment, bias Present general trends without comment, bias or