MR Y12 - Statistics

Question 1

Population

Answer 1

The whole set of items that are of interest e.g population of a town

Question 2

Raw data

Answer 2

Unprocessed data

Question 3

Census

Answer 3

A procedure observing or measuring every member of a population

Question 4

Sample

Answer 4

A selection of observations from a subset of a population used to find information about the population as a whole

Question 5

Advantages and disadvantages of a census

Answer 5

Advantages:
- Should give a completely accurate result

Disadvantages:
- Time consuming and expensive
- Hard to process the large quantity of data

Question 6

Advantages and disadvantages of a sample

Answer 6

Advantages:
- Less time consuming and expensive than a census
- Fewer people are required to respond
- Less data to process than a census

Disadvantages:
- Data may not be accurate
- Sample may not be large enough to provide information about small sub-sections of the population

Question 7

Sampling units

Answer 7

Individual units of a population

Question 8

Random sampling

Answer 8

Non-biased selection where every member of the population has an equal chance of being selected

Question 9

Simple random sampling

Answer 9

Where every sample has an equal chance of being selected e.g picking names out of a hat

Question 10

Systematic sampling

Answer 10

Where elements are chosen at regular intervals from an ordered list

Question 11

Stratified sampling

Answer 11

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

Question 12

Advantages and disadvantages of simple random sampling

Answer 12

Advantages:
- Free of bias
- Easy and cheap to implement for small sample sizes

Disadvantages:
- A sample frame is needed
- Not suitable for large population sizes due to being time consuming and expensive

Question 13

Two types of non-random sampling

Answer 13

Quota sampling
Opportunity sampling

Question 14

Three types of random sampling

Answer 14

Simple random sampling
Systematic sampling
Stratified sampling

Question 15

Quota sampling

Answer 15

Where a sample is selected to reflect the characteristics of the whole population

Question 16

Opportunity sampling

Answer 16

Where the sample is taken from people who are available at the time the study is carried out who fit the criteria

Question 17

Advantages and disadvantages quota sampling

Answer 17

Advantages:
- Allows a small sample to be representative of the population
- Allows easy comparison between different groups in the population

Disadvantages:
- Non-random sampling can introduce bias
- Population must be divided into groups which may be expensive or inaccurate

Question 18

Advantages and disadvantages of opportunity sampling

Answer 18

Advantages:
- Easy to carry out
- Inexpensive

Disadvantage:
- Unlikely to be representative
- Highly dependent on the researcher

Question 19

Quantitative data / variables

Answer 19

Data / variables associated with numerical observations

Question 20

Qualitative data / variables

Answer 20

Data / variables which are associated with non-numerical observations

Question 21

Continuous variable

Answer 21

A variable that can take any value in a given range

Question 22

Discrete variable

Answer 22

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

Question 23

Class boundaries

Answer 23

Maximum and minimum values that belong in each class

Question 24

Midpoint

Answer 24

Average of the class boundaries

Question 25

Class width

Answer 25

Difference between the upper and lower class boundaries

Question 26

Sampling frame

Answer 26

When units of a population are given individual names / numbers to form a list called a sampling frame