Experiments

Observational study

A research method that involves observing subjects in their natural environment without manipulation or intervention, often used to gather data on behaviors or conditions.

Experiment

A research method involving the manipulation of variables to determine effects on subjects, typically conducted in controlled settings.

Lurking variable

A variable that is not included in the study but may influence the relationship between the variables being studied, potentially leading to misleading conclusions.

Confounding

2 variables associated in a way that the effects on each other cannot be concluded, caused by a lurking variable.

Treatment

A condition applied in an experiment to observe its effects on the subjects.

Experimental units

The subjects or objects upon which a treatment is applied in an experiment, used to assess the effects of the treatment.

Subjects

The individuals or entities participating in an experiment, receiving treatments to evaluate the impact of those treatments.

Random assignment

A method used in experiments to randomly allocate subjects to different treatment groups, ensuring that each subject has an equal chance of being assigned to any group, which helps to eliminate bias.

Completely randomized design

A type of experimental design where all experimental units are assigned to treatments completely at random, allowing for the elimination of bias in treatment assignments.

Control

A group in an experiment that does not receive the treatment, used for comparison against the experimental group.

Replication

Repeating an experimental condition to verify results and ensure reliability.

Simple randomized comparative experiment

An experimental design that compares two or more treatments by randomly assigning subjects to different treatment groups to assess their effects.

Double blind experiment

A study design in which neither the participants nor the experimenters know who is receiving a particular treatment, reducing bias.

Single blind experiment

A study design in which participants do not know whether they are receiving the treatment or a placebo, while the experimenters do know, which helps to minimize participant bias.

Nonadherers

Refusals

Dropouts

Statistically significant

A result is statistically significant when it is unlikely to have occurred by chance, indicating a meaningful difference or effect in the data.

Block

is a method used in experimental design to group experimental units that are similar, to reduce variability and improve the accuracy of the results. (Example: having two groups of blue and red clothing in an experiment about different hot and cold water cleanliness levels)

Random block design

is a type of experimental design that involves dividing subjects into blocks based on shared characteristics, and then randomly assigning treatments within those blocks to reduce variability.

Matched pair design

is an experimental design that pairs subjects based on similar characteristics, allowing for the comparison of treatments within each pair while controlling for variability. It can also pair treatments and give subjects treatments to go to, the order is randomized. This causes the subject to be their own control.

Placebo

a substance with no therapeutic effect used as a control in testing new drugs, helping to determine the efficacy of the treatment by comparing results with those receiving the active ingredient.