Data collection

Question 1

Population

Answer 1

A whole set of items that are of interest

Question 2

Census

Answer 2

Observes or measures everyone in the population

Question 3

Sample

Answer 3

A subset of the population that is used to gather information about the whole population

Question 4

Simple random sampling

Answer 4

Every member of the population has an equal chance of being chosen

Question 5

Systematic sampling

Answer 5

Elements are chosen at regular intervals from an ordered list

Question 6

Stratified sampling

Answer 6

Population is divided into different strata and a random sample is taken from each

Question 7

Formula for stratified sampling

Answer 7

(no in a stratum/no in population) x overall sample size

Question 8

Quota sampling

Answer 8

A researcher selects a sample the reflects the characteristics of the whole population

Question 9

Opportunity sampling

Answer 9

Taking the sample from people who are available at the time the study is happening who also fit the criteria.

Question 10

Advantages of a census

Answer 10

It should give a completely accurate result

Question 11

Disads of a census

Answer 11

• Time consuming/expensive
• Hard to process large quantities of data
• Can’t be used when the testing process destroys the item

Question 12

Advantages of sampling

Answer 12

• Less time consuming/expensive
  . Less data to process
• Less people have to respond

Question 13

Disads of samples

Answer 13

• Data may not be accurate

- Sample may not be big enough to give info about everyone

Question 14

Ads of simple random sampling

Answer 14

• Free of bias
• Easy and cheap to do for small samples/pop.
• Each sampling unit has an equal chance of selection

Question 15

Disads of SRS

Answer 15

• Not good for large populations/samples bc it’s time consuming/expensive otherwise
• A sampling frame is needed

Question 16

Advantages of Systematic sampling

Answer 16

• Simple/quick

- Good for big samples/pop.

Question 17

Disads of systematic sampling

Answer 17

• needs sampling frame

- It could into. bias if frame isn’t random

Question 18

Ads of Strat.

Answer 18

• Accurately represents population structure

- Guarantees PR of groups in a populations.

Question 19

Disads of Strat

Answer 19

• Pop. has to be clearly classified into distinct groups

- Within each group, the disadvanatge is == to SRS disads..

Question 20

Ads of quota sampling

Answer 20

• Allows a small sample to be rep. of pop.
• No frame needed
• Quick, easy, cheap
• Allows for easy comparison between diff groups in a pop.

Question 21

Disads of quota sampling

Answer 21

• non-random sampling can give bias
• Population has to be split into groups which can be $$$
• Increasing the scope of study increases no. of groups- time waste

Question 22

Advantages of opportunity sampling

Answer 22

• Easy to do

- Cheap

Question 23

Disads of opportunity sampling

Answer 23

• Not gonna give a representative sample

- Highly dependent on person who does the sample

Question 24

Discrete data

Answer 24

Fixed data e.g the amount of people in a room – you cannot have 2.65 people in a room

Question 25

Continuous data

Answer 25

Values that can have decimal points – like weight, height etc