Design of experiments

thumb|Apollo 15 astronaut [[David Scott performs a gravity test on the Moon with a hammer and feather (1971).]] thumb|right|160px|Even very young children perform rudimentary experiments to learn about the world and how things work.

tendency of people to favor information that confirms their beliefs or hypotheses

collection of statistical models used to analyze the differences between group means and their associated procedures

method of statistical inference

human subject research in medicine

statistical concept

experimental method designed to reduce bias, typically accomplished by randomly allocating subjects to two or more groups, with one being a control group

experiment in which information about the test is masked to reduce bias

square array with symbols that each occur once per row and column

concept in mathematical modeling, statistical modeling and experimental sciences

scientific craft

set of research ethics principles for human experimentation

study with repeated observations over time

class=skin-invert-image|thumb|upright=1.3|Whereas a mediator is a factor in the causal chain (above), a confounder is a spurious factor incorrectly implying causation (bottom)

concepts from statistical hypothesis testing

process of gathering and measuring information

inventive process of finding new medications based on the knowledge of a biological target

type of observational study comparing two existing groups differing in outcome

In statistics, multicollinearity or collinearity is a situation where the predictors in a regression model are linearly dependent.

way of measuring the amount of information that an observable random variable carries about an unknown parameter of a distribution that models it

study that draws inferences from a sample to a population, in cases where the independent variable is not under the control of the researcher because of ethical concerns or logistical constraints

science and research term for a quality of a studied object

A quasi-experiment is a research design used to estimate the causal impact of an intervention. Quasi-experiments share similarities with experiments and randomized controlled trials, but specifically lack random assignment to treatment or control. Instead, quasi-experimental designs typically compare groups that are either preexisting (e.g., different dog breeds) or groups that were created without random assignment (e.g., students attending different universities).

Randomization is a statistical process in which a random mechanism is employed to select a sample from a population or assign subjects to different groups. The process is crucial in ensuring the random allocation of experimental units or treatment protocols, thereby minimizing selection bias and enhancing the statistical validity. It facilitates the objective comparison of treatment effects in experimental design, as it equates groups statistically by balancing both known and unknown factors at the outset of the study. In statistical terms, it underpins the principle of probabilistic equivalen

famous randomized experiment

experiment whose design consists of two or more factors, each with discrete possible values, and whose experimental units take on all possible combinations of these levels across all such factors

form of reactivity in which a researcher's cognitive bias causes them to subconsciously influence the participants of an experiment

steps for human subject medical research

predefined written procedural method in the design and implementation of experiments in natural sciences

use of data mining to uncover patterns in data that can be presented as statistically significant

social sciences statistical technique that mimics an experimental research design using observational study data by studying the differential effect of a treatment on a 'treatment group' versus a 'control group' in a natural experiment

statistical methods to improve the quality of manufactured goods

statistical method

set together with a family of subsets in math

research study in which both the researcher and the participant know which treatment is being used

A type of block design, specifically a t-design with λ = 1 and t ≥ 2.

in statistics, the situation in which the simultaneous influence of two variables on a third is not additive

procedure for comparing multivariate sample means

matrix of values of explanatory variables of a set of objects

studies of risk-modifying factors on health or other outcomes based on populations defined either geographically or temporally

sequential experimentation for improvement and for finding an optimal response

in statistics, a non-significant result

symmetric arrangement of finite sets

statistical analysis where the sample size is not fixed in advance

situation in which individuals select themselves into a group, causing a biased sample with nonprobability sampling

hospital or other institutional committees established to protect the welfare of research subjects

procedure to independently assess the methodological quality of a clinical trial

process involving chance used in research for allocating experimental subjects to groups

clinical trial that aims at establishing the safety and efficacy of a vaccine prior to it being licensed

technique used to compare populations with different age profiles

experiment conducted outside the laboratory

engineering method used when an outcome of interest cannot be easily directly measured, so a model of the outcome is used instead

experiment using randomness in some aspect, usually to aid in removal of bias

type experimental design in a clinical trial

group of experimental subjects which the study's design treats in a distinct way

type of research experiment

inequality encountered in block design

causal inference method

statistical method for generating a near-random sample of parameter values from a multidimensional distribution

A procedure that breaks up the task of identifying certain objects into tests on groups of items.