Discuss the main cause of variance in research.Discuss four basic techniques for controlling variance in research?

The main cause of variance in research is the presence of multiple factors that can influence the outcome of a study. These factors can include individual differences among participants, measurement error, random chance, and extraneous variables that were not accounted for in the study design. Variance can also be caused by the way data is collected, analyzed, and interpreted.

Four basic techniques for controlling variance in research include:

1. Randomization: Randomization involves assigning participants to different groups or conditions in a study in a random manner. This helps to ensure that any differences observed between groups are due to the intervention being studied and not to other factors.

2. Standardization: Standardization involves using consistent procedures and measures throughout a study to minimize variability. This can include using standardized tests, protocols, and procedures to ensure that data is collected in a consistent and reliable manner.

3. Matching: Matching involves pairing participants in different groups based on specific characteristics to control for potential confounding variables. This helps to ensure that any differences observed between groups are not due to differences in these characteristics.

4. Statistical control: Statistical control involves using statistical techniques to account for and control for potential sources of variance in a study. This can include using analysis of covariance (ANCOVA) to control for baseline differences between groups, or using regression analysis to control for the effects of potential confounding variables.

By using these techniques, researchers can help to minimize variance in their studies and increase the validity and reliability of their findings.