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Flashcards in Statistics C1 Deck (26)
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1

Population

The whole set of items that are of interest

2

Census

Observes or measures every member of a population

3

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

4

Adv of a Census

It should give a completely accurate result

5

Dis of Census

Time consuming
Expensive
Cannot be used if it destroys the item

6

Adv of a sample

Less time consuming
Less expensive
Less data to process

7

Did of a sample

May not be accurate
May not be large enough to give information about all sub groups of a population

8

Sampling units

Individual units of a population

9

Name 3 methods of random sampling

Simple random sampling
Systematic sampling
Stratified sampling

10

Systematic sampling

The required elements are chosen at regular intervals from an ordered list.
EG- sample size of 20 from population of 100
100÷20=5 interval

11

Stratified sampling

The population is divided into mutually exclusive strata (males and females) and a random sample is taken from each

Number samples in a stratum = (number in stratum/number in population)×overall sample siza

12

Adv of Simple random sampling

Free of bias
Easy and cheap for SMALL populations and samples

13

Did of Simple random sampling

Not good for BIG populations or samples
A sampling frame is needed

14

Adv of Systematic sampling

Simple and quick
Good for large samples and populations

15

Dis of Systematic samplinf

A sampling frame is needed
It can introduce bias if sampling frame isn't random

16

Adv of stratified sampling

Accurately represents population
Guarantees proportional representation

17

Dis of stratified sampling

Population must be classified in strata
A sampling frame is needed

18

Quota sampling

An interviewer selects a sample that reflects the characteristics of the whole population

19

Opportunity/convenience sampling

A sample is taken from people available at the time who fit the criteria

20

Adv of quota sampling

No sampling frame needed
Inexpensive and quick
Easy comparison between groups
Allows small sample to be representative

21

Dis of quota sampling

Non-random could be biased
Population must be in groups
Increasing scope makes it expensive
Dependent on an individual researcher

22

Quantitative variables

Numerical data

23

Qualitative variables

Non numerical values

24

Continuous variable

Can take any value

25

Discrete variable

Can only take specific values
EG: Number of girls in value cannot be 2.85 it has to be 2 or 3

26

Sampling frame

A list of the names or number of every unit in a population