Page 377 - Statistics for Dummies
P. 377
361
Index
decisions based on results of, making
grand total, 298
informed, 277–278
graphing. See also misleading graphs
defi ned, 262
conditional distributions, 306–308
double-blind, 57–58
ethical issues, 272–273
joint distributions, 304–305
fake treatment, 265–266
marginal distributions, 300–302
no treatment, 267
graphing categorical data
overview, 12, 56–58, 264
bar graphs, 97–102
pie charts, 92–97
placebo, 57
graphing numerical data
placebo effect, 265–266
boxplots, 115–122
random assignments of subjects to
treatments, 269–270
histograms, 103–115
time charts, 123–127
sample size, selecting, 267–268
standard treatment, 266
groupings in histograms, 105–106, 112–114
guidelines for p-values, 224
subjects, choosing, 268–269
treatment group, 57, 266
• H •
volunteers, fi nding, 269
explanatory variable, 287 generalizing research results, 276–277 361
extrapolation, 292 high percentiles, 153–154
histograms
• F • borderline values in, 106
center of data, 107, 109
factor, 262 creating, 104–106
fake treatment, 265–266 described, 16, 74–76, 103–104
false alarms, 225–226 evaluating, 110–112
fantasy sports, 28 fl at, 109
fatality rate, 25 frequency, 104
finite values, 46 groupings, 105–106, 112–114
five-number summary, 89–90 interpreting, 106–110
flat histograms, 109 mean (average), 109
following up surveys, 257–259 median, 109
formulas misleading, 112–115
being comfortable using, 336–337 misleading graphs, 323
for finding binomial probabilities, 137–140 outliers in, 109
for Z-distribution (standard normal relative frequency, 104
distribution), 147 scale, 114
frequency setting up, 105–106
in bar graphs, 97 shape of data, 106–109
described, 14, 97 showing ages of best actress Oscar
in histograms, 104 winners, 104–111
skewed left, 107, 111–112
• G • skewed right, 107, 111–112
spread of data, 106
Gallup Organization, 182, 191, 255 symmetric, 107, 111–112
“garbage in equals garbage out,” 13 time charts compared, 124
tips for, 111
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