Index 375

interaction, 296–297

interaction terms, 237, 329

intercept, 215, 221, 224–225, 272, 329

intercept row, 224

interim analysis, 76

International Conference on Harmonization

(ICH), 72

International Review Board (IRB), 72

Internet sources. See also G*Power; Microsoft

Excel

ClinCalc, 14

Comprehensive R Archive Network (CRAN), 58

Epi Info, 59

GraphPad, 67

International Business Machines, 57

National Health and Nutrition Examination

Survey (NHANES), 82, 86, 93, 148–157

National Institutes of Health (NIH), 72–73

OpenStat and LazStats, 59

Power and Sample Size Calculation (PS), 60,

171–172, 324–325

SAS OnDemand for Academics (ODA), 55–56

Statista, 34

StatPages, 158, 190, 282

interpolation, 208

inter-quartile range (IQR), 120

inter-rater reliability, 188–190

interval data, 102

intervention-related measurements, 63

interventions, 61–62

intra-rater reliability, 188–190

IQR (inter-quartile range), 120

IRB (International Review Board), 72

iterative models, 246–247

K

Kaplan-Meier method, 313–316, 328, 330

Kaplan-Meier (K-M) survival estimate, 313, 317

kappa (κ), 189–190

kilograms (kg), 218–220, 225–226, 239

Kruskal, William (statistician), 141

Kruskal-Wallis test, 47–49, 144, 157

kurtosis, 121–122

L

Last Observation Carried Forward (LOCF), 75

last-seen date, 303

LazStats, 59

least-squares line, 234

left skewed data, 121

leptokurtic distribution, 122

lethal dose, 262

levels of measurement, 102–103

LFU (lost to follow-up), 303–304, 308–309

life sciences, 1

life-table method, 307, 311–316, 320–321

likert scale, 102, 106

line of best fit, 215–216

linear combination, 329

linear function, 210–211

linear model, 272–273

linear regression, 210

link function, 273–274

liver cancer, 93–97

locally weighted scatterplot smoothing (LOWESS)

curve-fitting, 12, 286–290

LOCF (Last Observation Carried Forward), 75

logarithms, 21–22, 118–119

logistic regression

basics of, 251–254

definition of, 12, 210

disadvantages of, 266–268

evaluating, 257–265

sample size for, 268–269

using, 249–250, 255–257

log-normal distribution, 36, 125, 353–354

log-rank test, 317–325, 328–330

longitudinal research, 90

lost to follow-up (LFU), 303–304, 308–309