An R Companion to Political Analysis, Fourth Edition

Defined terms: base version of R, Comprehensive R Archive Network (CRAN), datasets, integrated development environment (IDE), missing package problem, package dependency, packages, R console, R session, RCPA4

Defined terms: assign, assignment operator, arguments, character string, charts, companion functions, data frame, function, generic syntax, global environment, indexing, keyword matching, list, matrices, missing value (NA), object, open source, optional arguments, packages, positional matching, R console, R session, R documentation, R scripts, required arguments, scalars, subset, tables, vector, working directory, workspace

Defined terms: bar chart, binary variables, bins, categorical variable, central tendency, continuous variables, cumulative percentage, discrete variables, dispersion, factor, frequency distribution table, histogram, interquartile range, interval-level, kurtosis, level of measurement, logical values, nominal-level, numeric, ordered factors, ordinal-level, range, ratio variables, sampling weight, skewness, standard deviation, unordered factors, unweighted data, variance, weighted data

Defined terms: additive index, attributes, center, class attribute, concatenate, cutpoints, dummy variables, factor, interval notation, levels, logical operators, logical values, mathematical operators, metadata, missing value (NA), numeric, NULL, per capita, recoding protocol, standardize, variable labels, $z$ scores

Defined terms: checking your code, column percentages, counts, cross-tabulations, debugging, dependent variable, factor and numeric variables, independent variable, mean comparison analysis, mean comparison table, observation-level data, summary data

Defined terms: aggregated data, base R graphics, box plots, clustered bar chart, formula syntax, graphical parameters, grammar of graphics, graphics device, interquartile range, jitter, layers, markers, mosaic plot, multiple line chart, outliers, overplotting, scatterplot, simple bar chart, simple line chart, strip chart

Defined terms: cluster random sample, clusters, comments, discrete distribution, human subjects, period, population, random assignment, random seed value, replication, robustness checks, sample, sampling with replacement, simple random sample, starting value, stratified random sample, stratum, systematic random sample

Defined terms: additive relationships, control variable, controlled comparison, controlled cross-tabulation, controlled mean comparison table, direction, factor, interactive relationship, legend, numeric, spurious relationship, strength

Defined terms: binomial distribution, confidence intervals, critical values, cumulative density function, degrees of freedom, empirical rule, inferential statistics, margin of error, normal distribution, point estimate, population, population parameters, probability, probability density function, probability distribution, quantile function, sample, sampling distributions, simulation, standard deviation, standard error, standard error of a sample mean, standard error of a sample proportion, standard normal distribution, $t$ distribution, $z$ scores

Defined terms: alpha, alternative hypothesis, assumptions about variance, confidence intervals, critical values, directional hypothesis, null hypothesis, null hypothesis significance testing (NHST), one-tailed and two-tailed $P$-values, one-tailed test, one-sample test, $P$-value, $P$-value approach, paired observations, pooled variance, research hypothesis, standard error, statistical significance, $t$ statistic, two-sample test, Type I and Type II errors, $z$ statistic

Defined terms: analysis of variance (ANOVA), asymmetrical measure, chi-square distribution, chi-square test statistic, concordant, discordant, and tied pairs, conditional distributions, Cramer’s $V$, degrees of freedom, expected frequencies, $F$ distribution, $F$ statistic, lambda, marginal distribution, measures of association, null hypothesis, observed frequencies, omnibus test, $P$-value, proportional reduction in error (PRE), single-factor, Somers’ $d$, statistical independence, statistical significance, sum of squares between groups, sum of squares within groups, symmetrical measure, total sum of squares, two-factor

Defined terms: academic-style table, adjusted R-squared, bivariate regression model, coefficients table, correlation matrix, expected or fitted values, intercept and slope coefficients, linear regression line, model object, ordinary least squares (OLS), other correlation coefficients, Pearson’s correlation coefficient, regression coefficient, R-squared, scatterplot

Defined terms: additive regression model, base terms, bubble plot, character expansion, confidence bar, dummy variables, interaction term, model object, multiple regression analysis, parallel regression lines, partial effect, prediction frame, reference category, regression plane, three-dimensional figures

Defined terms: assumptions of linear regression model, Breusch-Pagan test, fitted values, histogram of regression residuals, homoscedasticity and heteroscedasticity, influential observation, Jarque-Bera test, leverage, model object, normal distribution, observed values, outliers, Q-Q plots, regression residuals, residual standard error, residuals vs. fitted plot, squared residuals, standardized residuals, sum of squared errors, two components of regression model

Defined terms: binary variables, classification table, deviance, full effect, instantaneous effect, inverse logit, logged odds, logistic regression, marginal effect, marginal effects at representative values, marginal effects at the means, model object, odds, odds ratio, predicted probability curves, prediction frame, probability, pseudo R-squared measures, $z$ statistic

Defined terms: comma separated values, codebook, data import, limitations, literature review, metadata, Microsoft Excel, package dependencies, .rda or .RData file, .rds file, rectangular data, replication datasets, SPSS, Stata, working directory