Accurately represents reality

connect to face validity

What is the importance of randomization?

• Allows us to better ascertain that we are not getting idiosyncratic results
• aids in increasing generalizability 

• group that includes all the cases in which the researcher is interested
• A subset of the defined population aka who/ what we actually attempt to study

Simple Random Sampling

Probability or Not Probability 

• probability 
• all people in the population have an equal chance at being selected.
• being chose out of a hat

Systematic Random Sampling

Probability or Not Probability 

• probability
• members from a larger population are selected according to a random starting point and a fixed periodic interval
• start at a random place, then count every ten after that till you have the desired number of participants 

Stratified Random Sampling

Probability or Not Probability 

• Probability 
• used to equally represent all subgroups/strata (proportionate) or over-represent some subgroups (disproportionate).

Cluster Sampling

Probability or Not Probability

• Probability
• seperate clusters within the population are chosen.

Multistage Cluster Sampling

Probability or Not Probability 

• Probability
• randomly choose clusters and then randomly choose subjects from each cluster

Convenience Sampling

Probability or Not Probability 

• nonprobability
• literally who is around

Quota Sampling

Probability or Not Probability 

• Nonprobability 
• who is around that best fits into desired catergory 

Purposive Sampling

Probability or Not Probability 

• Nonprobability
• convenience sampling but choosing respondents specifically because of some key aspect

Snowball Sampling

Probability or Not Probability 

• Nonprobability
• having an initial respondent refer others to participate