Quiz

You want to obtain a sample of 100 Tahoe residents.  You make sure that 20 are below the age of 20, 30 are between 20 and 40 years old, 30 are between 40 and 60 years old, and 10 are older than 60.  What type of sampling is this?

A.  simple random sampling

B.  stratified sampling

C.  cluster sampling

D.  convenience sampling