Stats (Definitions)

HideShow resource information
Population
A whole set of items that are of interest
1 of 18
Census
Observes / measures every member of the population
2 of 18
Sample
A selection of observations taken from a subset of the population, which is used to find out information about the population as a whole.
3 of 18
Census (Advantages, disadvantages)
+: Should give a completely accurate result; -: Time consuming and expensive, hard to process a large quantity of data, cannot be used when testing destroys the item.
4 of 18
Sample (Advantages, disadvantages)
+: Less time consuming and expensive, fewer people have to respond, less data to process; -: Data may not be as accurate, sample may not be large enough to give info about sub-groups of population
5 of 18
Sampling units
Individual units of a population, which are often individually named/numbered to form a sampling frame.
6 of 18
Types of sampling
Simple random, systematic, stratified
7 of 18
Systematic sampling
Required elements are chosen at regular intervals from an ordered list.
8 of 18
Simple random sampling
Samples are randomly chosen. In a sample of 'n', there is a '1/n' chance of anyone being picked.
9 of 18
Stratified sampling
Population is divided into mutually exclusive strata e.g men/women , and a random sample is taken from each.
10 of 18
Simple random sampling (Advantages/disadvantages)
+: Free of bias, easy and cheap to implement for small popns, each sampling unit has = chance of selection; -: Not suitable when population size / sample size is large, sampling frame needed. ..........................................................
11 of 18
Systematic sampling (Advantages/disadvantages)
+: Simple and quick to use, suitable for large samples/ populations; -: Sampling frame needed, can introduce bias if sampling frame isn't random.
12 of 18
Stratified sampling (Advantages/disadvantages)
+: Sample accurately reflects population structure, guarantees proportional representation of groups within populations; -: Popn. must be clearly classified into strata, selection from each stratum has same disadvantages as simple random sampling
13 of 18
Types of non-random sampling
Quota, oppurtunity
14 of 18
Quota Sampling
A researcher selects a sample that reflects the characteristics of the whole popn.
15 of 18
Opportunity sampling
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
16 of 18
Quota Sampling (Advantages/disadvantages)
+: Allows a small sample to be representative, no sampling frame required, quick easy & inexpensive, allows for easy comp. between diff groups; -: Can introduce bias, popn. must be divided into groups which can be £££/inaccurate, adding groups £££
17 of 18
Opportunity Sampling (Advantages/disadvantages)
+: Easy to carry out, inexpensive; -: Unlikely to be representative, highly dependent on researcher
18 of 18

Other cards in this set

Card 2

Front

Observes / measures every member of the population

Back

Census

Card 3

Front

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

Back

Preview of the back of card 3

Card 4

Front

+: Should give a completely accurate result; -: Time consuming and expensive, hard to process a large quantity of data, cannot be used when testing destroys the item.

Back

Preview of the back of card 4

Card 5

Front

+: Less time consuming and expensive, fewer people have to respond, less data to process; -: Data may not be as accurate, sample may not be large enough to give info about sub-groups of population

Back

Preview of the back of card 5
View more cards

Comments

No comments have yet been made

Similar Mathematics resources:

See all Mathematics resources »See all Statistics, averages and distributions resources »