variable bias
41Randomized controlled trial — Flowchart of four phases (enrollment, intervention allocation, follow up, and data analysis) of a parallel randomized trial of two groups, modified from the CONSORT (Consolidated Standards of Reporting Trials) 2010 Statement[1] …
42Operational amplifier applications — This article illustrates some typical applications of operational amplifiers. A simplified schematic notation is used, and the reader is reminded that many details such as device selection and power supply connections are not shown. Contents 1… …
43Heckman correction — The Heckman correction (the two stage method, Heckman s lambda or the Heckit method) is any of a number of related statistical methods developed by James Heckman in 1976 through 1979 which allow the researcher to correct for selection bias.… …
44PIN diode — Layers of a PIN diode A PIN diode is a diode with a wide, lightly doped near intrinsic semiconductor region between a p type semiconductor and an n type semiconductor region. The p type and n type regions are typically heavily doped because they… …
45Outline of logic — The following outline is provided as an overview of and topical guide to logic: Logic – formal science of using reason, considered a branch of both philosophy and mathematics. Logic investigates and classifies the structure of statements and… …
46Linear regression — Example of simple linear regression, which has one independent variable In statistics, linear regression is an approach to modeling the relationship between a scalar variable y and one or more explanatory variables denoted X. The case of one… …
47Variance — In probability theory and statistics, the variance of a random variable, probability distribution, or sample is one measure of statistical dispersion, averaging the squared distance of its possible values from the expected value (mean). Whereas… …
48Meta-analysis — In statistics, a meta analysis combines the results of several studies that address a set of related research hypotheses. In its simplest form, this is normally by identification of a common measure of effect size, for which a weighted average… …
49Epidemiology — For the Community episode, see Epidemiology (Community). Epidemiology is the study of health event, health characteristic, or health determinant patterns in a population. It is the cornerstone method of public health research, and helps inform… …
50Scanning tunneling spectroscopy — (STS) is a powerful experimental technique in scanning tunneling microscopy (STM) that uses a scanning tunneling microscope (STM) to probe the local density of electronic states (LDOS) and band gap of surfaces and materials on surfaces at the… …
