# Formulae: Unit 14

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• Created by: annanolan
• Created on: 21-11-16 18:03
What is population?
The set of terms that you are interested in
1 of 17
What is a census?
A survey of the whole population
2 of 17
What is a sample?
A smaller number of items from the population
3 of 17
How do you reduce bias?
The sample must represent the whole population
4 of 17
What are strata?
When the population is divided into groups such as age range or gender
5 of 17
What is a stratified sample?
When the number of people taken from each group is proportional to the group size
6 of 17
What is a cumulative frequency diagram?
A graph with data values on the x axis and cumulative frequency on the y axis
7 of 17
How do you estimate the lower quartile on a cumulative frequency diagram?
The n/4th value
8 of 17
How do you estimate the upper quartile on a cumulative frequency diagram?
The 3n/4th value
9 of 17
Where do you plot the point in grouped data?
On the upper bound of the group
10 of 17
How do you work out the upper quartile for a set of n data values?
The UQ is the 3(n+1)/4th value
11 of 17
How do you work out the lower quartile for a set of n data values?
The LQ is the n+1/4th value
12 of 17
What is a comparative box plot?
Box plots for two different sets of data in the same diagram
13 of 17
What is a histogram?
A frequency diagram used for grouped continuous data where the class intervals are unequal
14 of 17
How do you calculate frequency density?
frequency / class width
15 of 17
How do you describe a date set?
Give a measure of average and a measure of spread
16 of 17
How do you compare data sets?
Compare a measure of average and a measure of spread
17 of 17

## Other cards in this set

### Card 2

#### Front

What is a census?

#### Back

A survey of the whole population

### Card 3

#### Front

What is a sample?

#### Back ### Card 4

#### Front

How do you reduce bias?

#### Back ### Card 5

What are strata?

#### Back 