Page 373 - Statistics for Dummies

Index
• Symbols and
• B •
Numerics •
bad sample, 49
bar graphs
> (greater than), 141
described, 16
> (greater than or equal to), 141
evaluating, 102
90th percentile (top 10%), 155
frequency, 97
68-95-99.7% rule, 53, 81–83, 112
horizontal, 102
10th percentile (bottom 10%), 155
misleading, 320–321
overview, 97
• A •
relative frequency, 97
scale of, 100–101
ACT scores, comparing, 87–89 for state lottery profi ts, 99–100
alpha level, 223 tips for, 102
alternative hypothesis, 61, 217 for tracking transportation expenses,
analyses 97–99

confidence interval, 18 vertical, 102
correlation, 20 for workplace pet peeves, 101–102
data from experiments, 274–277 bell-shaped curve, 54–55
data in surveys, 259 best-fi tting line
hypothesis tests, 18–19 calculating, 288–290
margin of error, 18 described, 286
overview, 17–18 example, 291–292
regression, 20 interpreting, 290–291
two-way tables, 20 linear regression, 286, 288–292
anecdotes slope of, 289–291

avoiding influence of, 330 y-intercept, 289–290
as factor in misleading statistics, 40 bias
anonymous respondents, 257 in data, 274
arithmetic errors, 34 described, 49
average (mean) in experiments, 13–14
binomials, 142 overview, 51
boxplots, 120 sources of, 323–324
calculating, 71–73 in surveys, 13–
histograms, 109 biased sample, 191
median compared with, 74–76 big picture information determined with
normal distribution, 143 t-table, 162
overview, 51–52 bimodal data set, 113
population, 51 binomial distribution
random variables, 134 described, 16
sample, 51 mean, 142
sampling distribution, 164–166 standard deviation, 142
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