Statistics How To

Normal distribution curve index > How to find the area between two z values on opposite sides of the mean If you want to find the area between two z-scores, the technique will differ slightly depending on if you have two z-scores on one side of the mean or on opposite sides of the mean. … Read more

Bayesian Statistics > A Bayes factor is the ratio of the likelihood of one particular hypothesis to the likelihood of another. It can be interpreted as a measure of the strength of evidence in favor of one theory among two competing theories. That’s because the Bayes factor gives us a way to evaluate the data … Read more

RCTs > Post marketing surveillance is the monitoring of drugs and other medical products after they have been initially approved and introduced to the market. It is part of the science of pharmacovigilance, which is the study of, detection, assessment, and prevention of drug related problems such as side effects, adverse outcomes, or lack of … Read more

Statistics definitions > What is Absolute Standard Deviation? There isn’t a clear definition for the term “absolute standard deviation.” You might sometimes see in a text book, lab notes, lecture notes, or some other in-class materials; the author is usually referring the “traditional” standard deviation. However, it might also refer to error propagation, relative standard … Read more

Statistics Definitions > The Asch paradigm, in psychology, is a series of experiments on conformity run by Solomon Asch in the 1950s. These experiments tested the way individuals responded to group-think, and to what extent social pressure could cause a person to conform. The Initial Asch Conformity Experiment In the initial experiment, a test subject … Read more

Descriptive Statistics: Charts and Graphs > A ribbon diagram is a 3D representation of the structure of a protein. It is used both by structural biologists and chemists as well as students and those with only a casual interest in molecular biology. Ribbon diagrams are also known as Richardson diagrams, after Jane S. Richardson who … Read more

Statistics Definitions > The limits of agreement approach analyzes: The way in which two ways of taking measurements agree, The extent to which they are compatible. More specifically, the method gives an estimate of the interval where a proportion of the differences lie between measurements. It is used when you are interested in trying a … Read more

Sampling > Total population sampling is a type of purposive sampling where the whole population of interest (i.e., a group whose members all share a given characteristic) is studied. It is most practical when the total population is of manageable size, such as a well-defined subgroup of a larger population. For example, total population sampling … Read more

Randomized Clinical Trials > A large simple trial, or LST, is a medical trial that involves a very large number of patients, typically over 1,000 participants. Because of the large-scale nature of the trial, it’s usually only feasible if it is stripped of all unnecessary complications. Entry requirements are usually very basic. An example of … Read more

Types of Variables > A concomitant variable, or covariate, is a variable which we observe during the course of our research or statistical analysis, but we cannot control it and it is not the focus of our analysis. Although concomitant variables are not given any central recognition, they may be confounding or interacting with the … Read more