Contents

484 Subject IndexNonprobability sampling, 144Nonreactive measures. See Reactivity;Unobtrusive measuresNovelty effects (threats to internalvalidity), 319–320, 330–331Null hypothesis (H 0 ) (defined), 208,385, 398. See also Nullhypothesis significance testing(NHST)Null hypothesis significance testing(NHST). See also Analysisof variance (ANOVA); Chisquaretest; F-test; t-testalpha and, 208, 385approach to data analysis, 208–209,384–388comparing two means, 390–396,405–406critical values and, 208–209defined, 208effect size and, 391errors and, 210–211, 387–388independent groups and, 390–396,410–414interpreting results of, 389level of significance, 208–209, 389mixed design, 414–416power and, 388–390, 395–396repeated measures designs and,243, 391–392, 407–410reporting results of, 394–395statistical significanceand, 208, 385Nuremberg Code, 61Observationbias and, 101–103, 131–132blind, 132, 201control and, 30–33data analysis of, 119–126demand characteristics and, 127direct vs. indirect, 96–97electronic tracking, 118–119ethical issues, 70–72, 99–100,129–130field experiments, 105–106goals, 93influence of observer, 126–129Internet and, 119intervention and, 97, 100–106methods, classification of, 96–97naturalistic, 97–100participant, 100–103reactivity and, 100, 106–107,126–129reliability of, 124–126sampling and, 94–96scientific vs. nonscientific,30–33, 93structured, 103–105unobtrusive (nonreactive), 96,106–112Observer (experimenter) biascontrolling, 132defined, 131, 200expectancy effects, 131Observer (influence of). See Demandcharacteristics; Expectancy(experimenter/observer)effects; Observer (experimenter)bias; ReactivityObserver reliabilitydefined, 124measures of, 125–126scientific reports and, 34Omnibus F-test. See Analysis ofvariance (ANOVA)One-group pretest–posttestdesign, 322Operational definitioncommunication and, 36criticisms of, 36defined, 35–36meaningfulness of, 35–36Oral presentations, 439–440Ordinal scale (measure), 115–118Outlier, 351Parameter, 360, 363Parsimony (rule of), 53Partial replications, 214Participant observationdefined, 100disguised vs. undisguised,100–103reactivity and, 127ethical issues, 100, 129–130Path analysis, 176–177Pearson Product-MomentCorrelation Coefficient,125–126, 173, 374–376.See also CorrelationPeer review, 422Percentage agreement(of observers), 125Personal interview, 150Physical tracesdefined, 107products, 107, 109rationale for use, 107–109types of, 107unobtrusive measures and, 107use, 107–109validity of, 109Placebo control, 200–201Plagiarism, 83–84Plausible alternative causes, 46–48,187, 191, 289Populationdefined, 141parameter, 360, 363sample vs. population, 141–147, 208sampling and, 141–143survey research and, 141–143Positive correlation, 125–126, 376.See also CorrelationPower (statistical)defined, 388experimental sensitivity and, 388factors affecting, 388independent groups designsand, 403–404NHST and, 389–390reporting, 390, 395sample size and, 388Practice effects (repeated measuresdesigns)anticipation effects and, 235balancing, 230–239controlling, 230–239counterbalancing, 230defined, 229–230differential transfer and, 243–244Precision of measurement. See alsoMeasurement of behaviorinstruments of, 36–37prediction and, 53theories and, 53Prediction as goal of scientificmethod, 40–41, 44–46, 53,138–177, 371. See also CorrelationPrediction (statistical). SeeCorrelationPrivacy, 70–72Probability sampling, 145–148Products (unobtrusive measures),107, 109Program evaluation, 310, 336–340Psychophysical methods(psychophysics), 228–281PsycINFO, 431Publication (of findings), 81–84,422, 439Publication credit, 82, 430Publication Manual (APA). SeeAmerican PsychologicalAssociation (APA)Qualitative researchanalysis of data, 119–122coding and, 120–122content analysis and, 120–122data reduction, 120defined, 44, 120narrative records, 113–114vs. quantitative research, 43–44,113–114, 119Quantitative research. See alsoAnalysis of dataanalysis of data, 120–122defined, 43measures of behavior, 115–119vs. qualitative research, 43–44,122–126Quasi-experimentsanalysis of, 334