STATISTICAL METHODS COMPARISONS

Question 1

2 pros of using a census

Answer 1

1) Accurate information on a population
2) Unbiased information as it represents whole population

Question 2

2 cons of using a census

Answer 2

1) Difficult to survey all members (e.g. will every person fill out the quiz?)
2) Impractical (e.g. cannot stress test every nail or there will be none left)

Question 3

2 pros of using a sample

Answer 3

1) Quicker, cheaper and easier than a census
2) Only option when surveyed members/items are used up or destroyed (e.g testing grenades)

Question 4

2 cons of using a sample

Answer 4

1) Variability between samples
2) Sampling bias

Question 5

Pro and con of random sampling

Answer 5

+) unbiased: every member of population has equal chance of selection
-) impractical if members are spread out over a large area

Question 6

Pro and con of systematic sampling

Answer 6

+) unbiased sample IF sampling frame is randomly ordered
-) bias is possible, e.g. if you sample every 10th item, but every 10th item produced happens to be faulty

Question 7

Pro and con of stratified sampling

Answer 7

+) likely provides a representative sample, unbiased if uses random sampling
-) Not useful when no obvious categories, can be expensive due to extra step

Question 8

Pro and con of quota sampling

Answer 8

+) does not require sampling frame
-) easily biased when using opportunity sampling to collect sample to meet quota

Question 9

Pro and con of opportunity sampling

Answer 9

+) data gathered quickly and easily
-) isn’t random, very easily becomes biased