# Statistics Flashcards Preview

## Edexcel A Level Maths > Statistics > Flashcards

Flashcards in Statistics Deck (23)
1
Q

Population

A

A set of items that are of interest

2
Q

Census

A

Measures every member of a population

3
Q

Sampling unit

A

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

4
Q

Sample

A

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

5
Q

Simple random sampling

A

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

6
Q

Systematic sampling

A

Members are chosen at regular intervals from an ordered list

7
Q

Stratified sampling

A

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

8
Q

A

Free of bias
Easy and cheap
Equal chance of selection

9
Q

A

Not suitable for a large population or sample size

10
Q

A

Simple and quick to use

Suitable for large samples and populations

11
Q

A

A sampling frame is needed

Possible bias because there is not an equal chance of selection

12
Q

A

Accurately reflects the population

Guarantees proportional representation of groups

13
Q

A

Can be time consuming

14
Q

Quota sampling

A

Similar to stratified

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

15
Q

Opportunity sampling

A

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

16
Q

Quantitative data

A

Numerical data (eg hight)

17
Q

Discrete data

A

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

18
Q

Qualitative data

A

Non numerical data (eg colour, or worded answers)

19
Q

Continuous data

A

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

20
Q

How do you tell that there isn’t a skew

A

Mean = median = mode

21
Q

How do you tell that there is a positive skew

A

Mean > median > mode

22
Q

How do you tell that there is a negative skew

A

Mean < median < mode

23
Q

What is variance

A

Standard deviation squared