Sampling

Question 1

What are the three methods of random sampling?

Answer 1

simple random sampling
systematic sampling
stratified sampling

Question 2

how is random sampling representative of a population?

Answer 2

every member of the population has an equal chance of being selected

Question 3

What does random sampling help remove from a sample?

Answer 3

bias

Question 4

what is a simple random sample of size n?

Answer 4

where every sample of a size n has an equal chance of being selected

Question 5

what happens in systematic sampling?

Answer 5

the required elements are chosen at regular intervals from an ordered list

e.g
sample size 20
population 100
= 100/20 = every 5th person

Question 6

what happens in stratified sampling?

Answer 6

the population is divided into mutually exclusive strata (e.g males and females) and a random sample is taken from each

Question 7

what formula can be used to calculate the number of people we should sample from each stratum?

Answer 7

number in stratum
——————————— x overall sample size
number in population