Sampling

Question 1

What is bias?

Answer 1

A systematic distortion.

Question 2

What are the 5 types of sampling?

Answer 2

Opportunity
Random
Stratified
Systematic
Volunteer

Question 3

What is systematic sampling?

Answer 3

Predetermined system such as every 4th member of a population. The numerical interval (n=4) is applied consistently.

Question 4

Give a strength of a volunteer sample.

Answer 4

Gives access to wide range of population (through newspaper).
May be easier or more plausible than other techniques such as full random sample.

Question 5

Describe how a stratified sample is obtained.

Answer 5

Subgroups (strata) within a population are identified (gender, age, race etc). Participants obtained from each strata in proportion to their occurrence in the population. Selection from strata is done using a random sampling technique.

Question 6

Name two random sampling techniques.

Answer 6

Lottery method
Random number generator

Question 7

What bias occurs when obtaining a volunteer sample?

Answer 7

Volunteer bias! Well done! Genius!

Question 8

What is a limitation of the systematic sampling technique?

Answer 8

Not truly unbiased unless a random number method is used to select which member of the population is n=1.