can anyone explain what that means. it can also be explained with pictures and sketches.

a) What do the abbreviations CAPI and CATI stand for? Give examples of some advantage and some disadvantage for each method

b) Describe the different types of dropouts that exist and what effects it can have on a sample survey. What can be done to counteract dropouts before and after an examination?

dc) Briefly explain the concept of snowball selection. Describe why it is sometimes used and what advantages and disadvantages it can have.