Data Collection

Question 1

Population

Answer 1

Whole set of items that are of interest

Question 2

Census

Answer 2

Observes or measures every member of a population

Question 3

Sample

Answer 3

Selection of observations taken from a subset of the population which is used to find out information about the population as a whole

Question 4

Dis and ad of census

Answer 4

Ad: should give a completely accurate result
Dis: time consuming and expensive
Cannot be used when testing process destroys the item
Hard to process large quantity of data

Question 5

Dis and ad of sample

Answer 5

Ad: less time consuming and expensive 
Fewer people have to respond
Less data to process
Dis: data may not be as accurate
Sample may not be large enough to give info about small subgroups of the population

Question 6

Sampling units

Answer 6

Individual units of a population

Question 7

Sampling frame

Answer 7

Sampling units of a population are individually named or numbered to form a list
A LIST OF

Question 8

Simple random sample of size n

Answer 8

Every sample of size n have an equal chance of being selected

Question 9

Systematic sampling

Answer 9

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

Question 10

How to do systematic sampling

Answer 10

List all data and number them
Use a random number generator to find a start point
Then select every n data until your sample size is reached
Use the corresponding data points to the numbers to form ur sample

Question 11

Stratified sampling

Answer 11

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

Question 12

The number sampled in a stratum for stratified

Answer 12

=number in stratum/number in population x overall sample size

Question 13

Simple random sampling dis and ad

Answer 13

Ad: free of bias
Easy and cheap to implement for small populations and small samples
Each sampling unit has a known and equal chance of selection
Dis: not suitable when the pop size or sample size is large as potentially time consuming, disruptive and expensive
Sampling frame is needed

Question 14

Systemic sampling ad and dis

Answer 14

Ad: simple and quick to use
Suitable for large samples and large populations
Dis: a sampling frame is needed
It can introduce bias if the sampling frame is not random

Question 15

Stratified sampling ad and dis

Answer 15

Ad: sample accurately reflects the population structure
Guarantees proportional representation of groups within a population
Dis: populations must be clearly classified into distinct strata
Selection within each stratum suffers from the same disadvantages as sampling random

Question 16

Quota sampling

Answer 16

An interviewer or researcher selects a sample that reflects the characteristics of the whole population

Question 17

Opportunity sampling

Answer 17

Consists of taking the sample from people who are available at the time the study is carried out and who fit the criteria you are looking for

Question 18

Quota sampling ad and dis

Answer 18

Ad: allows a small sample to still be representative of the population
No sampling frame required
Quick, easy and inexpensive
Allows for easy comparison between different groups with a population
Dis: non-random sampling can introduce bias
Pop must be divided into groups which can be costly or inaccurate
Increasing scope of study increases number of groups, which adds time and expense
Non-responses are not recorded as such

Question 19

Opportunity sampling ad and dis

Answer 19

Ad: easy to carry out
Inexpensive
Dis: unlikely to provide a representative sample
Highly dependant on individual researcher

Question 20

Quantitative data

Answer 20

Data associated with numerical observations

Question 21

Qualitative data

Answer 21

Data associated with non-numerical observations

Question 22

Continuous variable

Answer 22

A variable that can take an value in a given range

Question 23

Discrete variable

Answer 23

A variable that can take only specific values in a given range