Answer:
independent variable
An independent variable is defines as the variable that is changed or controlled in a scientific experiment. It represents the cause or reason for an outcome. Independent variables are the variables that the experimenter changes to test their dependent variable
dependent variable
The dependent variable is the variable being tested and measured in an experiment, and is 'dependent' on the independent variable. An example of a dependent variable is depression symptoms, which depends on the independent variable
experimental group
FDA uses the information from these tests to decide whether to test the vaccine with people. During a clinical trial, a vaccine is tested on people who volunteer to get vaccinated. Clinical trials start with 20 to 100 volunteers, but eventually include thousands of volunteers.
control group
There are valid scientific and ethical considerations for using a control group in a clinical trial. Placebo-controlled trials are justifiable when they are supported by sound methodologic consideration and when their use does not expose research participants to excessive risk of harm. Consideration should be given to “best available therapy” control groups in the evaluation of a new therapy or intervention over an existing therapy. Investigators should keep in mind that one should not sacrifice the scientific merit of a trial to include a best-available-therapy control group as long as the placebo control group poses little harm to participants and, importantly, the trial offers potential benefit to the subject. The pros and cons of using placebo versus best-available-therapy control groups are discussed.
