Data Collection

Question 1

Census

Answer 1

observes and measures every member of a population

Question 2

Sample

Answer 2

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

Question 3

Advantages and Disadvantages of a Census

Answer 3

+ should give a completely accurate result

• time consuming, expensive, hard to process large amount of data and cannot be used when testing process destroys item

Question 4

Advantages and Disadvantages of a Sample

Answer 4

+ less time consuming, more cost effective than census, fewer people have to respond, less data than census

• data is not as accurate, sample may not be large enough to give info about small sub-groups of a population

Question 5

Simple Random Sampling

Answer 5

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

Question 6

Systematic Sampling

Answer 6

required elements are chosen at regular intervals from an ordered list

Question 7

Stratified Sampling

Answer 7

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

Question 8

Advantages and Disadvantages of Simple Random Sampling

Answer 8

+ 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

• not suitable when the population size or the sample size is large, a sampling frame is needed

Question 9

Generating a sampling frame ; 2 Methods

Answer 9

generating random numbers and lottery sampling

Question 10

Advantages and Disadvantages of Systematic Sampling

Answer 10

+ simple and quick to use, suitable for large samples and large populations

• sampling frame is needed, can introduce bias if the sampling frame is not random

Question 11

Advantages and Disadvantages of Stratified Sampling

Answer 11

+ sample accurately reflects the population structure, guaruntees proportional representation of groups within a population

• population must be clearly classified into distinct strata, again may not accurately represent small subsets within a large population

Question 12

Quota Sampling

Answer 12

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

Question 13

Opportunity Sampling

Answer 13

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 14

Advantages and Disadvantages of Quota Sampling

Answer 14

+ allows a small sample to be representative of population, no sampling frame required, quick, easy and inexpensive, different groups within population are easily comparable

• non random sampling can introduce bias, pop. divided into groups which can be costly or inaccurate, increasing scope of study increases number of groups, which increases time and expense, non-responses are not recorded as such

Question 15

Advantages and Disadvantages of Opportunity Sampling

Answer 15

+ easy to carry out, inexpensive

• unlikely to provide a representative sample, highly dependant on individual researcher

Question 16

Quantitative Variables/Data

Answer 16

variables/data associated with numerical observations

Question 17

Qualitative Variables/Data

Answer 17

variables/data associated with non-numerical observations

Question 18

Continuous Variable

Answer 18

variable that can take any value in a given range

Question 19

Discrete Variable

Answer 19

variable that can only take specific values in a given range