Index 371

chronic obstructive pulmonary disease

(COPD), 302

CI (confidence interval)

calculating, 226

definition of, 10, 39, 130–131

using, 131–138, 183, 194–197

CIR (cumulative incidence rate), 178–179

CL (confidence level), 39

CL (confidence limits), 130, 134

classification tables, 262–264

ClinCalc, 172

clinical center variable, 338

clinical trials, 9–10, 61–74

cloud-based storage, 60

CLT (central-limit theorem), 134

cluster sampling, 84

Cochrane Collaboration, 297

code, 241

code-based methods, 60

coding categories, 105–107

coefficient of determination, 227

coefficient of variation (CV), 120

Cohen’s Kappa, 189

cohort study, 90, 93–96

collecting data

introduction to, 1–2, 9–10

manually and digitally, 74, 101–110

collinearity, 246–247, 266

commercial software, 54–58

common logarithms, 22

comparing averages, 142

complete separation, 267–268

complicated formulas, 24

Comprehensive R Archive Network (CRAN), 58

computer science, 18

computerized tomography (CAT) scans, 188

concordance, 342

confidence interval (CI)

calculating, 226

definition of, 10, 39, 130–131

using, 131–138, 183, 194–197

confidence level (CL), 39

confidence limits (CL), 130, 134

confidentiality, 71

confounding

adjusting for, 145, 294–296

criteria for, 292

definition of, 66, 94

residual, 68

constants, 17

contingency tables, 173–178, 184, 187–188

control group, 98, 154, 187

convenience sampling, 84–85

COPD (chronic obstructive pulmonary

disease), 302

coronary heart disease (CHD), 92–93

correlation, 40, 201–202, 220

correlation coefficient

analyzing, 203–207

description of, 202–203

example of, 10, 40

straight-line regression, 227–228

table, 242

correlational studies, 91–93

COVID-19, 183–184

Cox, David (biostatistician), 330

Cox proportional hazards regression, 330

Cox/Snell R-square, 259

CRAN (Comprehensive R Archive Network), 58

CRFs (case report forms), 74

crossover design, 65

cross-sectional studies, 87–96, 176

cross-tabulated data

analyzing, 160–167, 171–172

example of, 112–113, 166

introduction to, 11

relation to logistic regression, 250

tables, 173–174

cumulative incidence rate (CIR), 178–179

cumulative survival probability, 311–314

curved-line relationships, 214

CV (coefficient of variation), 120