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year 10 and 11 > Statistics > Flashcards

Flashcards in Statistics Deck (23)
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1

What are qualitative variables?

Have non-numerical observations

2

What is continuous data?

Measured on a scale and can take any value on that scale

3

What is Discrete data?

In most cases data concerned with a number of countable values

4

What is categorical data?

Data which have a scale grouped in different categories

5

What is ranking data?

Is ordered categories of data eg. Year groups in schools

6

What is bivariate data?

When every observation has two pieces of data (scatter graphs)

7

Primary data

Collected by or for the person who is going to use it
Advantages
~you know who and how it was collected
~you know accuracy and reliability
Disadvantages
~time consuming
~expensive
~limited to collecting from certain people

8

Secondary data

Not collected by or for the person who will use it
Advantages
~easy to find
~cheap
~larger sample than you can get yourself
~more representative of all people
Disadvantages
~don't know how it was collected so isn't fully reliable
~may be out of date
~might not quite fit with your purpose

9

What is a statistical experiment?

An experiment where one of the variables will always be controlled engle its affect on the other variable is observed

10

What does respondent mean?

It is what you call a person who has completed a questionnaire

11

How do you generate random numbers on a calculator?
For example between 1 and 32

Press ran#x32+1

Then truncate

12

What is a random sample?

Each item of the population has an equal chance of being selected

13

What is stratified sampling?

When you divide the population into categories/strata (by age, gender, social class ect.) and within these groups take a random sample proportional to the relative size from which the stratum is taken

14

What is systematic sampling?

A sample which is obtained by choosing at regular intervals from an ordered list

15

What is cluster sampling?

The population which is being tested is split into clusters then a cluster is randomly chosen and every item is looked at

16

What is quota sampling?

Instructions are given (by the surveyor) about the amount of each section of the population with a certain characteristic

17

What is Convenience sampling?

Choosing the first names on a list

18

What are pie charts?

They show proportions for each category (not frequencies) from the fraction of the circle

19

What is the formula for the histogram frequency density?

Frequency density=frequency / class width

Or

Frequency=frequency density x class width

20

What is the formula for Index numbers?

Index number= quantity / quantity in base year x 100

Simple index numbers:
Price relative=price/price in base year x100

21

What is an outlier?

An outlier is any value which is 1.5 (or more) times the inter quartile range below or above the interquartilerange

22

What is t PhD formula for standardised scores?

Standardised score= score-mean /
Standard deviation

23

What are quanta give variables?

Have numerical observations or measurements