QM 2113 - Spring 2002QM 2113 - Spring 2002

Business StatisticsBusiness Statistics

SPSS: A Summary SPSS: A Summary & Review& Review

AgendaAgenda HomeworkHomework

– Return bivariate analysis (Excel)• Questions about either Excel exercise• Comments about bivariate exercise

– Collect SPSS exercises SPSSSPSS

– Reminder: delete extraneous output– Filtering data– Copy/paste into Word or other applications– CrossTabs

• Define categories• Example comparing Excel and SPSS

– Inference (population mean)• Hypothesis test• Estimation

Manipulating DataManipulating Data

Refer to exercises due 4/5/2002Refer to exercises due 4/5/2002– Salary analysis

• Men versus women• Excel: filter, copy, paste, analyze

– Now, let’s look at using SPSS

FilteringFiltering– Data | Select Cases | If . . . – Now do analysis– Unfilter: Data | Select Cases | All Cases . . .

Analyzing Analyzing Qualitative DataQualitative Data

RecallRecall– Two types of data

• Qualitative (Gender and Computer Usage)• Quantitative (Salary, Age, . . . )

– Ordinal data can be treated as either quantitative or qualitative; categories with numerical order; e.g., Education and Job Classification

Analyzing relationship between two Analyzing relationship between two quantitative variables: regressionquantitative variables: regression

Analyzing relationship between two Analyzing relationship between two qualitative variables: crosstabsqualitative variables: crosstabs

Consider Gender Consider Gender versus Job versus Job

ClassificationClassification Does “job level” depend upon gender?Does “job level” depend upon gender? Simple frequency tablesSimple frequency tables

– Doesn’t tell us about how these variables are related

– Need to go further: crosstabulation Review of crosstabsReview of crosstabs

– Joint frequency: basis for developing the other three

– Joint relative frequency (% of total)– Analyzing relationships

• Multiplication rule• If independent, joint % = product of margin % values

Using Excel’s Using Excel’s PivotTable Feature PivotTable Feature

for Crosstabsfor Crosstabs Select the data, including headingsSelect the data, including headings Click on Data | PivotTableClick on Data | PivotTable Click twice on NextClick twice on Next Click on LayoutClick on Layout

– Drag Gender to row– Drag Job to column– Drag either to data– Double click on data button

• Select Count, then click on Options• In Show Data As, select % of Total• Click on OK

– Click on OK Click on FinishClick on Finish

Using SPSS Using SPSS CrosstabsCrosstabs

Analyze | Descriptives | CrosstabsAnalyze | Descriptives | Crosstabs Select row and column variablesSelect row and column variables Click on Cells buttonClick on Cells button

– Leave Observed checked for Counts– Check Total for Percentages

Resulting table corresponds to Resulting table corresponds to Excel PivotTableExcel PivotTable

AnalyzeAnalyze– P(Level | Gender) = P(Level)?– P(Level & Gender) = P(Level) x P(Gender)?

Inference: A Quick Inference: A Quick ReviewReview

Population or Process

Sample

Parameter

Statistic

Inferences

Estimation & Estimation & Hypothesis TestingHypothesis Testing

Hypothesis testingHypothesis testing– Start with an assumed population (or

process) parameter– Gather data and see if the statistic is likely,

given the assumption EstimationEstimation

– Start with a sample statistic– Use that statistic to create an interval

estimate The situation dictates which is The situation dictates which is

appropriate (sometimes either is)appropriate (sometimes either is)

Using SPSS for Using SPSS for Statistical InferenceStatistical Inference

Univariate analysisUnivariate analysis– Inference about averages, not proportions– Hypothesis testing:

• First, setup test (H0 & HA, , sketch, decision rule)• Then: Analyze | Compare Means | One-Sample t Test

– Estimation: Analyze | Descriptive Statistics | Explore

Relationship between two variablesRelationship between two variables– Both quantitative: Analyze | Regression– Both qualitative:

Analyze | Descriptive Statistics | Crosstabs– Quantitative dependent & qualitative independent:

Analyze | Compare Means | One-Way ANOVA

HomeworkHomework

CrossTabs exerciseCrossTabs exercise– Job Level vs Education– Use

• Excel• SPSS

Inference exercises with SPSSInference exercises with SPSS– Hypothesis test– Confidence interval estimates– Sample size determination