Describe and contrast selection bias and participation bias in sampling.

Selection bias occurs whenever
Participation bias occurs any time

Step 1 ：Selection bias refers to the bias that can occur when the sample that is being studied is not representative of the population it is supposed to represent due to flawed selection methods.

Step 2 ：Participation bias refers to the bias that can occur when the people who choose to participate in a study are not representative of the total population.

Step 3 ：The main difference between these two types of bias is that selection bias is about the method of selecting the sample, while participation bias is about who chooses to participate in the study.

Step 4 ：Both can lead to a sample that is not representative of the population, but they occur in different ways.