Basic Statistics

INDEX 255

straight line, 168

tests, 176

transformations, 183

Reject hypothesis, 109

Relative risk, 146

Residuals, 170

Risk factor, 4

S

Samping

Sample size

stratified, 15

two means, 11 1

two proportions, 136

case/control, 23
chunk samples, 21
economical, 20
experiments, 21
prospective studies, 23
random samples, 15
replacement, 19
simple random, 15, 17
surveys, 20
systematic, 16
Scatter diagram, 166
Sign test, 190
Skewed distributions, 77
Slope, 169
Spearman’s correlation, 198
Standard deviation, 52
Standard error of the mean, 85, 101
Stem and leaf, 36
Stevens’classification, 58
Student’s t distribution, 84
Student’s t test, 104
Summary of procedures for tests, 100
Surveys, 6
Survival analysis

Sampling

Kaplan-Meier estimates, 212

censored data, 203

clinical life tables, 208

comparing groups, 215

cumulative death density, 205

death density, 204

hazard function, 207

regression, 216

survival functions, 207

time to event, 202

T

Tests

approximate t test, 121

correlation, 179

equality of mean, 103

equality of means paired data, 107

equality of means using pooled variance, 104

equality of two proportions, 134

equality of variances, 118

nonparametric, 190

one-sided, 99

proportions, 133

regression coefficients, 176

sample mean, 96

sign test, 190

single mean with s, 101

Wilcoxon rank sum test, 195

Wilcoxon signed ranks test, 192

regression, 183

Transformations

Two-way frequency tables, 141

Two-way tables

chi-square for large tables, 158

components of chi-square, 160

confidence intervals, 149

continuity correction, 157

d.f. large tables, 159

Fisher’s exact test, 156

interpreting the results, 160

matched samples, 144

odds ratios, 147

relative risk, 146

sample size, 156

sample size for large tables, 161

single sample, 142

two samples, 143

v

Variables, 14

Variance, 53

test for equality, 118

W

Wilcoxon-Mann-Whitney test, 195

Wilcoxon rank sum test, 195

Wilcoxon signed ranks test, 192