Subject index. A about this book downloading programs...4 errata...19 example datasets... 4, 19

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1 Subject index A about this book downloading programs...4 errata...19 example datasets... 4, 19 GSS dataset online resources...19 overview Read me first...3 user-written programs... 4, 5 academic pricing, Stata...8 access to Stata source code added variable plots... added variable plots addplot() option, marginsplot command adjacent mean contrasts adjusted means... see ANCOVA, adjusted means technical details... see ANCOVA, adjusted means, technical details adjusted R-squared... see effect size, adjusted R-squared advantages of using Stata...see Stata strengths analysis of covariance...see ANCOVA analysis of variance...see ANOVA analyzing subsamples , analyzing summary data...see immediate commands ANCOVA adjusted means...138, 145, technical details ANCOVA, continued adjusted R-squared , 145, experiment with randomization observational data power analysis...see power analysis, ANCOVA randomized prepost design specifying covariates Stata video tutorial statistical power... see statistical power, ANCOVA unadjusted means using regress command , with interactions...see ANCOVA with interactions ANCOVA with interactions compared to two-way ANOVA contrasts of adjusted means graphing multiple comparisons contrasts of slopes estimating slopes graphing adjusted means graphing interaction three-level IV two-level IV ANOVA analyzing complex surveys heterogeneity of variance mixed-design... see mixed-designs

2 630 Subject index ANOVA, continued one-way... see one-way ANOVA power analysis...see power analysis, one-way ANOVA one-way repeated measures statistical power versus ANCOVA.. see statistical power, ANCOVA versus ANOVA supercharging three-way...see three-way ANOVA two-way...see two-way ANOVA power analysis...see power analysis, two-way ANOVA using median regression using qreg command using quantile regression using regress command using robust regression using robust standard errors using rreg command violating homogeneity of variance with influential observations with outliers anova command ANCOVA... see ANCOVA one-way ANOVA... see one-way ANOVA output explained three-way ANOVA...see three-way ANOVA two-way ANOVA...see two-way ANOVA versus regress command append command appending datasets as balanced versus as observed contrasts as observed versus as balanced contrasts asbalanced option asobserved option at() option, margins command , , , average marginal value versus marginal value at the mean avplots command B Beta coefficients...see regression, Beta coefficients; see also regression, intepreting coefficients beta option, regress command , 406, between-subjects ANOVA one-way... see one-way ANOVA three way...see three-way ANOVA two way...see two-way ANOVA between/within designs... see mixed-designs binomial exact test......see one-sample test of proportions, binomial exact bitest command bitesti command...54 Bonferroni adjustments , , 533, 550, 553 books, recommended by: prefix command bydimension() option marginsplot command byopts() option, marginsplot command C c. prefix caption() option, marginsplot command cases...see observations categorical predictors, using regress command , see also ANOVA cause and effect...18

3 Subject index 631 cell percentages.. see cross-tabulations, cell percentags chi-squared test.. see cross-tabulations, chi-squared test chi2 option tabi command tabulate command cimargins option, pwcompare command ciopts() option, marginsplot command clear command...26, clear option, use command clinical significance codebook command coefplot command see user-written programs, coefplot command; see also presenting regression results Cohen s d effect size..see effect size, Cohen s d power analysis...see power analysis, Cohen s d column percentages... see cross-tabulations, column percentages combining datasets comma-separated files exporting from Stata importing into Stata comparisons among means... see contrasts complex surveys computing new variables , see also modifying variables confidence intervals, interpreting confidence levels, setting contrast command , df() option effects option level() option , 524 mcompare() option noeffects option contrast command, continued nowald option pveffects option contrast operators a ar custom g gw h hw j jw p , pw q qw r table of weighted contrasts adjacent mean computing effect size , custom grand mean helmert polynomial , reference group reverse adjacent mean reverse helmert selecting , , , selecting reference group testing planned comparisons to previous levels to subsequent levels weighted converting datasets.. see Stat/Transfer Cook s D... see regression diagnostics, Cook s D cooksd option, predict command correlate command

4 632 Subject index correlations pairwise...50 Stata video tutorial covariance structures , covariates...18 by IV interaction...see ANCOVA with interactions increasing statistical power......see statistical power, increasing using covariates specifying in ANCOVA...see ANCOVA, specifying covariates covratio option, predict command creating formatted regression tables see presenting regression results creating new variables cross-tabulations...28, 34 36, 48 50, cell percentages chi-squared test Stata video tutorial... 49, 55 using summary data column percentages Fisher s exact test , Stata video tutorial... 49, 55 using summary data row percentages...36 Stata video tutorial...28, 49 using summary data Stata video tutorial...55 with summary statistics Stata video tutorial...37.csv files, importing into Stata custom contrasts D data conversion software... see Stat/Transfer Data Editor data management... 20, Stata strengths datasets appending combining converting... see Stat/Transfer describing documenting for this book... see about this book, example datasets GSS dataset..see about this book, GSS dataset merging reshaping long to wide reshaping wide to long viewing dependent groups t test...see paired sample t test dependent variable describe command describing datasets descriptive statistics Stata video tutorial df() option, contrast command DFBETA. DFBETA dfbeta command dfits option, predict command dfmethod() option, mixed command displaying stored results...see stored results, displaying documenting datasets downloading datasets for this book...see about this book, example datasets programs for this book... see about this book, downloading programs user-written programs see user-written programs, downloading drop command drop if command dropping observations dropping variables

5 Subject index 633 Duncan adjustments , 550, Dunnett adjustments , 550, DV...see dependent variable dydx() option, margins command E e(sample) stored result , ease of learning, Stata... 9 edit command...24 effect size adjusted R-squared , , 145, Cohen s d esize twosample command esizei command , estat esize command , 145, , eta-squared from contrasts , omega-squared R-squared Stata video tutorial effect, of variable effects option contrast command pwcompare command , egen command ereturn list command errata...see about this book, errata error covariance structures , error messages file already exists no; data in memory would be lost...26, previous command was not margins...67, esize twosample command esizei command , estat esize command , omega option... 69, estat vif command estimates dir command estimates stats command estimates store command , , estimates table command , estimation commands analyzing subsamples common features common syntax if specification robust standard errors setting confidence levels with prefix commands , by: mi estimate: nestreg: , 514 stepwise: svy: , esttab command see user-written programs, esttab command; see also presenting regression results eta-squared...see effect size, eta-squared exact option tabi command tabulate command example datasets..see about this book, example datasets Excel workbooks exporting from Stata exporting results to, Stata video tutorial exporting tabulations to...31 importing into Stata

6 634 Subject index Excel workbooks, continued saving regression tables as see presenting regression results, as Excel workbook Stata tutorial on importing Stata tutorial on pasting from..560 export delimited command export excel command exporting results to Excel, Stata video tutorial extremes command see user-written programs, extremes command F factor variables , see also independent variable Stata video tutorial used with margins command factorial design three way...see three-way ANOVA two way...see two-way ANOVA FAQs, Stata...12 Fisher s exact test...see crosstabulations, Fisher s exact test formatting regression tables...see presenting regression results forvalues command fre command...see user-written programs, fre command frequency distributions... see one-way tabulations G generate command Getting Started manual grand mean contrasts graph matrix command groups option, pwcompare command , , GSS dataset.. see about this book, GSS dataset H heterogeneity of variance heteroscedasticity... see regression diagnostics, homoscedasticity hierarchical regression.. see regression, nested models homogeneity of variance homoscedasticity...see regression diagnostics, homoscedasticity I i. prefix if specification , immediate commands bitesti command...54 esizei command , prtesti command tabi command ttesti command import delimited command import excel command importing comma-separated files importing.csv files importing Excel workbooks Stata video tutorial independent variable by covariate interaction...see ANCOVA with interactions influential observations ANOVA regression... influential observations interaction contrasts three-way ANOVA...see three-way ANOVA, interaction contrasts two-way ANOVA...see two-way ANOVA, interaction contrasts interactions covariate by IV..see ANCOVA with interactions three-way...see three-way ANOVA two-way...see two-way ANOVA internal validity...18

7 Subject index 635 interpreting confidence intervals IV...see independent variable K keep command keep if command keeping observations keeping variables L label define command label values command label variable command labeling values labeling variables L A TEX document, saving regression tables as...see presentingregressionresults, asl A TEX document legend() option, marginsplot command level() option contrast command...522, 524 regress command leverage. leverage leverage option, predict command leverage versus residual squared plot..... see regression diagnostics, leverage versus residual squared plot lincom command , linear regression...see regression linearity. linearity long datasets, reshaping to wide longitudinal designs , see also repeated measures designs IV by time interaction IV by time(piecewise) interaction longitudinal designs, continued linear effect of time piecewise modeling of time looping , see also looping lowess command lvr2plot command M main effects, interpreting with categorical interactions marginal value at the mean versus average marginal value marginally significant...see not significant margins command , , , asbalanced option asobserved option at() option , , , contrast() option dydx() option mcompare() option noatlegend option nopvalues option...65 use before marginsplot command...67, with factor variables marginsplot command , , adding scatterplot to addplot() option bydimension() option byopts() option ciopts() option customizing by-graphs customizing the legend displaying confidence intervals displaying fit line error messages previous command was not margins...67, 80 81

8 636 Subject index marginsplot command, continued labeling the plot dimension labeling the x dimension legend() option line thickness marker size marker symbol noci() option omitting confidence interval plotdimension() option plotopts() option recast() option recastci() option scheme() option selecting a scheme selecting dimension for x axis..543 selecting the by dimension selecting the plot dimension subtitle() option title() option use with margins command... 67, xdimension() option xlabel() option , 547 xscale() option xtitle() option ylabel() option yscale() option caption() option note() option ytitle() option matched pairs t test...see paired sample t test mcompare() option contrast command margins command pwcompare command , 550, median regression merge command merging datasets mi estimate: prefix command missing option, tabulate command mixed command dfmethod() option residuals() option , small-sample methods mixed-designs ANCOVA as alternative analysis residual covariance structures modifying variables multicollinearity...see regression diagnostics, multicollinearity multiple regression...see regression, multiple regression multiple-comparison adjustments , , 533, Bonferroni adjustments , , 533, 550, 553 Duncan adjustments , 550 Dunnett adjustments , 550 Scheffé adjustments , , 533, 550, 553 Šidák adjustments , , 533, 550, 553 Student Newman Keuls s adjustments , 550 Tukey adjustments , 550, 553 multiprocessing, Stata N nested regression models...see regression, nested models nestreg: prefix command , 514 noatlegend option, margins command noci() option, marginsplot command...542

9 Subject index 637 noeffects option, contrast command nonparametric statistics nopvalues option, margins command normality of residuals... normality of residuals not significant... see reanalyzing your data until you find a significant result note() option, marginsplot command notes command nowald option, contrast command O observational data, ANCOVA...see ANCOVA, observational data observations dropping keeping OLS regression...see regression omega option, estat esize command omega-squared...see effect size, omega-squared one-sample t test Stata video tutorial using summary data Stata video tutorial...53 one-sample test of proportions binomial exact using summary data...54 using summary data one-tailed tests one-way ANOVA, contrasts one-way repeated measures designs one-way tabulations one-way tabulations exporting to Excel Stata video tutorial with missing data with multiple variables...30 one-way ANOVA means of DV by IV confidence intervals graphing power analysis...see power analysis, one-way ANOVA online resources, for this book......see about this book, online resources online resources, Stata outliers ANOVA regression...see regression diagnostics, outliers output explained anova command regression command ttest command outreg command see user-written programs, outreg command; see also presenting regression results outreg2 command...see user-written programs, outreg2 command; see also presenting regression results overview, this book... see about this book, overview P paired sample t test Stata video tutorial pairwise comparisons pairwise correlations...50 partial correlation

10 638 Subject index partial interactions three-way ANOVA...see three-way ANOVA, partial interactions two-way ANOVA...see two-way ANOVA, partial interactions pasting Excel workbooks to Stata Stata video tutorial PDF documentation in Stata, Stata video tutorial...21 Pearson s correlation Stata video tutorial piecewise modeling of time...see longitudinal designs, piecewise modeling of time planned comparisons...see contrasts plotdimension() option, marginsplot command plotopts() option, marginsplot command point and click interface polynomial contrasts , postestimation commands , 517 contrast...see contrast command marginsplot...see marginsplot command margins...see margins command pwcompare...see pwcompare command listing of...82 power ability to reject a false null hypothesis...see statistical power sample size estimation..see power analysis power analysis , , see also statistical power ANCOVA ANOVA one-way two-way power analysis, continued Cohen s d guidelines related to R-squared nested regression one-way ANOVA regression standardized effect guidelines Stata video tutorial two-sample t test unequal group sizes two-way ANOVA power multreg command...see user-written programs, power multreg command power nestreg command...see user-written programs, power nestreg command practical significance...41 predict command cooksd option covratio option dfits option leverage option rstandard option , 490 rstudent option welsch option prefix commands...456, by: mi estimate: nestreg: , 514 stepwise: , 515 svy: , presentation quality regression tables..... see presenting regression results presenting regression results as Excel workbook as L A TEX document as.rtf file as.tex file as Word document as.xml file formatting coefficients

11 Subject index 639 presenting regression results, continued including confidence intervals labeling variables multiple models , one model , using coefplot command using estimates table command using esttab command using outreg command using outreg2 command using xml tab command previous levels, contrast to pricing, Stata...8 programs for this book... see about this book, downloading programs user-written...see user-written programs video tutorial on downloading proportions one-sample test...see one-sample test of proportions binomial exact......see one-sample test of proportions, binomial exact two-sample test...see two-sample test of proportions prtesti command pveffects option pwcompare command , pveffects option, contrast command pwcompare command , cimargins option effects option , groups option , , pwcompare command, continued mcompare() option , 550, pveffects option , sort option , pwcorr command...50 pwmean command Q qreg command quantile regression R R-squared...see effect size, R-squared randomized prepost design ANCOVA...see ANCOVA, randomized prepost design Read me first...3, see also about this book, Read me first reading data into Stata comma-separated files csv files Excel workbooks Stata datasets reanalyzing your data until you find a significant result..see multiple comparison adjustments recast() option, marginsplot command recastci() option, marginsplot command recode command recoding variables recommended books recommended resources reference group contrasts regress command beta option , 406, cformat() option computing summary statistics for estimation sample details about displaying stored results

12 640 Subject index regress command, continued for performing ANOVA formatting p-values formatting coefficients formatting standard errors identifying estimation sample level() option multiple regression nestreg: prefix command noheader option notable option options explained pformat() option redisplaying results setting confidence level sformat() option simple regression Stata video tutorial stepwise: prefix command stored results e(sample) storing results versus anova command regression Beta coefficients , 406, computing adjusted means computing predicted means computing summary statistics for estimation sample diagnostics...see regression diagnostics fitting multiple models on the same sample graphing predicted means homoscedasticity... see regression diagnostics, homoscedasticity regression, continued interpreting coefficients Beta coefficients multiple-unit change one-unit change standardized coefficients linearity... see regression diagnostics, linearity multicollinearity... see regression diagnostics, multicollinearity multiple regression nested models nonlinearity...see regression diagnostics, linearity outliers...see regression diagnostics, outliers output explained partial correlation power analysis...see power analysis, regression presenting results... see presenting regression results robust standard errors semipartial correlation simple regression standardized coefficients , 406, standardized residuals... standardized residuals Stata video tutorial stepwise models studentized residuals... studentized residuals testing multiple coefficients equal to zero equality of coefficients linear combinations

13 Subject index 641 regression, continued variance inflation factor... variance inflation factor VIF. VIF regression diagnostics added variable plots Cook s D COVRATIO DFBETA DFITS excluding suspect observations homoskedasticity influential observations leverage leverage versus residual squared plot linearity assessing analytically assessing graphically assessing using contrast command assessing via factor variables assessing via graphing means assessing via lowess assessing via polynomials assessing via residuals assessing via scatterplots multicollinearity normality of residuals outliers scatterplot matrix standardized residuals studentized residuals variance inflation factor VIF Welsch distance repeated measures designs , see also longitudinal designs analyzing using ANCOVA mixed-designs... see mixed-designs one-way residual covariance structures , repeating commands with loops replace command replace option, save command reproducing results required sample size...see power analysis reshape long command reshape wide command reshaping datasets long to wide wide to long residual covariance structures , residuals normality... normality of residuals standardized... standardized residuals studentized... studentized residuals residuals() option, mixed command , robust regression robust standard errors ANOVA estimation commands regression row percentages.. see cross-tabulations, row percentags rreg command rstandard option, predict command , 490

14 642 Subject index rstudent option, predict command rtf file, saving regression tables as see presenting regression results, as.rtf file rvfplot command...474, S sample size estimation...see power analysis save command replace option saving Stata datasets Scheffé adjustments , , 533, 550, 553 scheme() option, marginsplot command search command selecting contrasts , , , selecting reference group semipartial correlation showcoding command see user-written programs, showcoding command Šidák adjustments , , 533, 550, 553 significance...41 simple contrasts three-way ANOVA...see three-way ANOVA, simple contrasts two-way ANOVA...see two-way ANOVA, simple contrasts simple effects three-way ANOVA...see three-way ANOVA, simple effects two-way ANOVA...see two-way ANOVA, simple effects simple interactions, three-way ANOVA... see three-way ANOVA, simple interactions simple partial interactions, three-way ANOVA.... see three-way ANOVA, simple partial interactions simple regression...see regression, simple regression sort option, pwcompare command , source code, Stata...11 speed, of Stata split plot designs...see mixed-designs SPSS commands, Stata equivalents.... see Stata equivalents of SPSS commands SSC archive ssc command standardized coefficients... see regression, standardized coefficients; see also regression, intepreting coefficients standardized effect Cohen s d..see effect size, Cohen s d power analysis...see power analysis, standardized effect standardized residuals... standardized residuals Stat/Transfer...8, Stata Blog...12 Stata equivalents of SPSS commands ADD FILES AGGREGATE ANOVA AUTORECODE CASESTOVARS COMPUTE CROSSTABS DELETE VARIABLES DESCRIPTIVES DISPLAY DOCUMENT FACTOR FILTER FORMATS FREQUENCIES GET FILE GET TRANSLATE LOGISTIC REGRESSION...606

15 Subject index 643 Stata equivalents of SPSS commands, continued MATCH FILES MEANS MISSING VALUES MIXED MULTIPLE IMPUTATION NOMREG PLUM PROBIT RECODE RELIABILITY RENAME VARIABLES SAVE SAVE TRANSLATE SELECT IF SORT CASES SORT VARIABLES SUMMARIZE T-TEST VALUE LABELS VARIABLE LABELS VARSTOCASES Stata estimation commands...see estimation commands Stata interface, Stata video tutorial..20 Stata Journal Stata manuals, Stata video tutorial..21 Stata Press books Stata pricing...8 Stata source code...11 Stata strengths access to source code...11 ANOVA ANOVA technology...8 data management ease of learning...9 economical...8 FAQs...12 multiprocessing online resources point and click interface...11 powerful and simple...11 pricing...8 Stata strengths, continued speed Stata Blog...12 Stata Journal Stata Technical Bulletin...13 Stata/MP Statalist statistical powerhouse user-written programs , see also user-written programs video tutorials on Stata...12 Stata Technical Bulletin Stata video tutorials...see video tutorials on Stata Stata web forum...12 Stata website Stata YouTube channel... see video tutorials on Stata Stata/MP Statalist...12 statistical power , , see also power analysis ANCOVA versus ANOVA ANCOVA ANCOVA versus ANOVA ANCOVA versus repeated measures ANOVA increasing using covariates statistical significance...41 stepwise regression models... see regression, stepwise models stepwise: prefix command , 515 stored results displaying e(sample) regress command storing results , structure of residual covariance , student pricing, Stata...8 Student Newman Keuls s adjustments , 550,

16 644 Subject index studentized residuals... studentized residuals subsamples, analyzing , subsequent levels, contrast to subtitle() option, marginsplot command summarize command with if specification summary data, analyzing...see immediate commands summary statistics by one variable by two variables for subgroups svy: prefix command , T t test one-sample..see one-sample t test paired sample...see paired sample t test two-sample..see two-sample t test tab1 command...30 tabi command chi2 option exact option tabulate command chi2 option exact option missing option one-way.. see one-way tabulations Stata video tutorial two-way... see cross-tabulations with summarize() option tabulations one-way.. see one-way tabulations two-way... see cross-tabulations test command testparm command tex file, saving regression tables as see presenting regression results, as.tex file three-way ANOVA interaction contrasts partial interactions , simple contrasts...244, 256 simple effects...239, 256 simple interactions , 242, simple partial interactions three-by-three-by-three design interaction contrasts partial interactions simple contrasts simple effects simple interactions two-by-two-by-three design partial interactions simple contrasts simple interactions simple partial interactions two-by-two-by-two design simple effects simple interactions time as a continuous predictor...see longitudinal designs piecewise modeling of...see longitudinal designs, piecewise modeling of time title() option, marginsplot command treatment effect...18 ttesti command Tukey adjustments , 550, two-sample t test , 51 52, 59 63, Cohen s d output explained

17 Subject index 645 two-sample t test, continued power analysis...see power analysis, two-sample t test Stata video tutorial using summary data Stata video tutorial...52 two-sample test of proportions using summary data...53 two-way ANOVA CIs, interpreting interaction contrasts interpreting CIs partial interactions , , power analysis...see power analysis, two-way ANOVA simple contrasts , simple effects , , , 188 Stata video tutorial three-by-three design interaction contrasts partial interactions simple contrasts simple effects two-by-three design partial interactions , simple contrasts simple effects , two-by-two design simple effects unbalanced designs two-way tabulations...see cross-tabulations U UCLA IDRE website unadjusted means, ANCOVA...see ANCOVA, unadjusted means use command...26, clear option user-written programs coefplot command downloading Stata video tutorial...10 esttab command...4 5, extremes command...5 for this book... see about this book, downloading programs fre command...4, outreg command outreg2 command power multreg command... 4, power nestreg command... 4, showcoding command...4 xml tab command V value labels variable labels variables creating new dropping keeping modifying recoding variance inflation factor..see regression diagnostics, variance inflation factor vce(robust) option , 489, 512 video tutorials on Stata exporting results to Excel video tutorials on Stata ANCOVA with interactions chi-squared test...49 using summary data...54 converting datasets correlation...51 cross-tabulations... 28, 49 using summary data...54 cross-tabulations and summary statistics...37

18 646 Subject index video tutorials on Stata, continued descriptive statistics...38 downloading user-written programs...10 effect sizes Excel workbooks importing pasting data into factor variables...63 factorial ANOVAwith interactions Fisher s exact test...49 using summary data...54 getting help in Stata...20 importing Excel workbooks to Stata interactions, factorial ANOVA linear regression one-sample t test, using summary data...53 one-way tabulations...28 paste Excel workbooks to Stata PDF documentation in Stata...21 power analysis regress command Stat/Transfer Stata interface Stata manuals...21 t test one-sample...43 paired sample...42 two-sample tabulate command...49 two-sample t test, using summary data...52 two-way ANOVA user-written programs, downloading...10 viewing datasets...24 viewsource command...11 VIF. VIF W web resources, Stata web site for this book...see about this book, online resources weighted contrasts welsch option, predict command..464 Why use Stata...see Stata strengths wide datasets, reshaping to long within subjects designs within/between designs... see mixed-designs Word document, saving regression tables as...see presenting regression results, as Word document X xdimension() option, marginsplot command xlabel() option, marginsplot command...540, 547.xml file, saving regression tables as see presenting regression results, as.xml file xml tab command... see user-written programs, xml tab command; see also presenting regression results xscale() option, marginsplot command xtitle() option, marginsplot command Y ylabel() option, marginsplot command YouTube channel, Stata...see video tutorials on Stata yscale() option, marginsplot command ytitle() option, marginsplot command...540