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A-Level EDEXCEL Maths > Statistics > Flashcards

Flashcards in Statistics Deck (29)
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1

Define population

A set of items that are of interest

2

Define census

A measure of every member of a population

3

What is meant by a sampling unit?

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

4

Give an advantage of a census

Completely accurate result

5

Give 3 advantages of a sample

- Less time-consuming
- Fewer responses needed
- Less data to process

6

Give 3 disadvantages of a census

- Time consuming
- Cannot be used if the sampling process would render the items unusable
- Processing a lot of data takes a long time

7

Give 2 disadvantages of a sample

- Data might not be accurate
- Sample might not be properly representative of the population

8

Describe simple random sampling

Selecting members will involve assigning numbers to all members of the set, and generating numbers at random to choose them

9

Describe systematic sampling

members are chosen at regular intervals from an ordered list

10

Describe stratified sampling

Dividing the population into groups and randomly choosing the same number from each group

11

Give 3 advantages of simple random sampling

- Free of bias
- Easy and cheap to implement
- Every unit has an equal chance of selection

12

Give 2 advantages of systematic sampling

- Simple and quick to use
- Suitable for large samples and populations

13

Give 2 advantages of stratified sampling

- Sample accurately reflects the population
- Guarantees proportional representation of groups

14

Give 3 disadvantages of simple random sampling

- Not suitable for a large population or sample size
- A sampling frame is needed

15

Give 2 disadvantages of systematic sampling

- A sampling frame is needed
- Possible bias as units do not have an equal chance of selection

16

Give 2 disadvantages of stratified sampling

- Population must be classified into groups which can be time-consuming
- Selection within a group has the same issues as simple random sampling

17

Give the 2 types of non-random sampling

- Quota
- Opportunity

18

What is quota sampling?

Where an interviewer or researcher selects a sample that reflects the characteristics of the group

19

What is opportunity sampling?

Where the sample is taken from people available at the time and who fit the criteria needed

20

Give 3 advantages of quota sampling

- Allows a small sample to represent the population
- No sampling frame required
- Quick and inexpensive
Allows comparison between groups

21

Give 4 disadvantages of quota sampling

- Potential for bias to be introduced
- Can take time to divide the population into groups after
- A more in-depth study would require an increasing number of different groups
- Some people might not be willing to take part

22

Give 2 advantages of opportunity sampling

- Easy to carry out
- Inexpensive

23

Give 3 disadvantages of opportunity sampling

- Unlikely to give a proportional sample
- Researcher’s ability can affect the outcome
- People might not want to be interviewed/asked

24

Define quantitative data

Data which is numerical

25

Define qualitative data

Data which is non-numerical

26

What is discrete data?

Data which can only take certain values

27

What's continuous data?

Data which can take any value

28

What are class boundaries?

maximum and minimum values that belong in a group

29

What is the classwidth

the difference between the upper and lower class boundaries