| A | B |
|---|
| negative correlation | a relationship between two variables in which one variable increases as the other decreases, and vice versa. |
| positive correlation | a relationship between two variables that move in tandem—that is, in the same direction |
| double-blind study | neither the participants nor the researcher knows which treatment or intervention participants are receiving until the clinical trial is over. |
| single-blind study | only the researcher doing the study knows which treatment the participant is receiving until the trial is over. |
| placebo effect | a beneficial effect produced by a placebo drug or treatment (a fake drug or treatment) and must therefore be due to the patient's belief in that treatment. |
| confounding variables | outside influence that changes the effect of a dependent and independent variable. |
| control group | the individuals that does not receive the new treatment being studied |
| control variables | the part of experiment that's kept the same throughout an experiment. |
