Page 382 - Statistics for Dummies

366
Statistics For Dummies, 2nd Edition
• Q •
response, 262
response bias, 256
qualitative data (categorical data). See also
response rate, 258
graphing categorical data
response variable, 287
calculating, 68–71
results
described, 68, 91
decisions based on results of experiments,
summaries for, 14, 15
making informed, 277–278
quantitative data, 46
generalizing research, 276–277
questions on surveys, formulating, 253–254
implications of research, 276
overstated, 21, 275–276
• R •
reporting, 186–187
surveys, interpreting results of, 259–260
random assignments of subjects to
right-tail probability, 160
treatments in experiments, 269–270
Rumsey, Deborah
random digit dialing (RDD), 49
Probability For Dummies, 100
random samples
Statistics II For Dummies, 262, 288, 293, 308
checking for, 325
described, 49–50, 255 residuals, 293
selecting, 13 • S •
random variables. See also binomials
mean, 134 sample mean
overview, 131–132, 163–164 described, 51, 72
standard deviation, 134 margin of error (MOE), 187–188
rates, 36 probabilities for, fi nding, 173–174
real exam conditions, practicing for exam sample proportion
under, 334–336 margin of error (MOE), 184–186
reasonableness of projections, examining, 34 sampling distribution, 175–177
regression, 20 sample selection
regression line described, 13
calculating, 288–290 surveys, 254–256
described, 286 sample size
example, 291–292 checking, 325–326

interpreting, 290–291 confidence intervals, 199–200, 204–206
linear regression, 286, 288–292 defi ning, 268
slope of, 289–291 determining needed, 204–206
y-intercept, 289–290 as factor in misleading statistics, 39–40
relative frequency margin of error (MOE), 189–191
in bar graphs, 97 selecting, 267–268
described, 14, 97 standard error, 166–167
in histograms, 104 t-distribution, 159
relative standing, 53, 84 sample statistics, gathering, 218
reliability of data, 273 sample variability, measuring, 183–184
research process, 43–45 sample variance, 77
research question design samples
with experiments, 12 bad, 49
overview, 11 described, 48–50, 254
with surveys, 11–12 non-random, 49–50
random, 49–50, 255
3/25/11 8:12 PM
32_9780470911082-bindex.indd 366
32_9780470911082-bindex.indd 366 3/25/11 8:12 PM