RESEARCH METHODOLOGY

Detailed explanation-1: -Due to a flaw in the sample selection process, a subset of the data is excluded from the study, thereby impacting or negating the statistical significance of the test. There are several types of sample selection bias, including pre-screening bias, self-selection bias, exclusion bias, and observer bias.

Detailed explanation-2: -Selection bias is a kind of error that occurs when the researcher decides who is going to be studied. It is usually associated with research where the selection of participants isn’t random (i.e. with observational studies such as cohort, case-control and cross-sectional studies).

Detailed explanation-3: -Selection bias occurs when the association between exposure and health outcome is different for those who complete a study compared with those who are in the target population.

Detailed explanation-4: -Sample selection bias is any systematic difference between the sample and the population. It affects the internal validity of an analysis by leading to inaccurate estimation of relationships between variables.