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~may be out of date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