Statistics

Question 1

Population

Answer 1

A set of items that are of interest

Question 2

Census

Answer 2

Measures every member of a population

Question 3

Sampling unit

Answer 3

A selection of the population used to estimate information about the population as a whole

Question 4

Sample

Answer 4

A selection of the population used to estimate information about the population as a whole

Question 5

Simple random sampling

Answer 5

Every element in the set has an equal chance of being selected

Question 6

Systematic sampling

Answer 6

Members are chosen at regular intervals from an ordered list

Question 7

Stratified sampling

Answer 7

The population is divided into groups e.g. male and female. The proportions should reflect the proportions of the population as a whole

Question 8

Advantages of simple random sampling

Answer 8

Free of bias
Easy and cheap
Equal chance of selection

Question 9

Disadvantage of simple random sampling

Answer 9

Not suitable for a large population or sample size

Question 10

Advantages of systematic sampling

Answer 10

Simple and quick to use

Suitable for large samples and populations

Question 11

Disadvantages of systematic sampling

Answer 11

A sampling frame is needed

Possible bias because there is not an equal chance of selection

Question 12

Advantages of stratified sampling

Answer 12

Accurately reflects the population

Guarantees proportional representation of groups

Question 13

Disadvantages of stratified sampling

Answer 13

Can be time consuming

Question 14

Quota sampling

Answer 14

Similar to stratified

A researcher will select a sample that reflects the characteristics of the group

Question 15

Opportunity sampling

Answer 15

The sample is taken from people available at the time and who fit the criteria needed
Like random

Question 16

Quantitative data

Answer 16

Numerical data (eg hight)

Question 17

Discrete data

Answer 17

Data which can only take certain values (eg only an integer)

Question 18

Qualitative data

Answer 18

Non numerical data (eg colour, or worded answers)

Question 19

Continuous data

Answer 19

Data that can take any value (eg height, length)

Question 20

How do you tell that there isn’t a skew

Answer 20

Mean = median = mode

Question 21

How do you tell that there is a positive skew

Answer 21

Mean > median > mode

Question 22

How do you tell that there is a negative skew

Answer 22

Mean < median < mode

Question 23

What is variance

Answer 23

Standard deviation squared