Chapter 2: Processing and Representing Data Flashcards
What are databases?
Tables with a collection of data
Databases are a form of secondary data available online and often easily accessible.
What is bivariate data?
Data with two variables
Two-way tables contain bivariate data.
What can you calculate from tables?
Totals, differences, percentages
You can also describe trends and explain inconsistencies.
True or False: Percentages in a table always add up to 100%.
False
This is often due to rounding errors.
What is a pictogram?
Uses pictures or symbols to represent data
Each symbol represents a specific amount of data.
What are the characteristics of simple bar charts?
- Bars of equal width
- Equal gaps between bars
- Frequency on y-axis
Simple bar charts display categorical data.
What is the purpose of a key in a pictogram?
To show the amount each symbol represents
This ensures clarity in data representation.
What do composite bar charts compare?
Different categories over time
They have single bars split into sections for each category.
How are stem and leaf diagrams useful?
Organize data without losing detail
They show the shape of the distribution and retain original data.
What does a population pyramid indicate?
Distribution of ages in a population
It can show proportions or percentages.
What do choropleth maps represent?
Geographical areas shaded to indicate frequency
Darker shading indicates higher frequency.
Define cumulative frequency.
A running total of frequencies
It helps in understanding data distribution.
How do you calculate the median from a cumulative frequency diagram?
Divide total frequency by 2, then find on Y-axis
Draw a horizontal line to read off the value from the x-axis.
What is the formula for frequency density?
Frequency / Class Width
Frequency density reflects concentration of values.
What indicates the shape of a population distribution?
The shape of the population pyramid
An upright pyramid indicates a younger population.
How to draw a pie chart?
Calculate angles for each frequency and ensure they add up to 360°
Label the sectors appropriately.
What do comparative pie charts compare?
Two sets of data of different sizes
The areas should be in the same ratio as the frequencies.
What do histograms represent?
Continuous data from grouped frequency tables
There are no gaps between bars.
What is the significance of equal class widths in histograms?
They ensure uniformity in data representation
The x-axis represents data while the y-axis represents frequency.
Fill in the blank: The _______ of a pie chart equals the total frequency.
Area
This helps in comparing different pie charts.
What should you check when interpreting pie charts?
Proportions, not numbers
This helps in understanding the data representation accurately.
What is the formula for Frequency Density (FD)?
FD = F/CW
F = frequency, CW = class width
What should be labelled on the y-axis when drawing a histogram?
Frequency density
How should the bars in a histogram be drawn?
Bars have no gaps in between
What is the first step in estimating frequencies from histograms?
Calculate class widths and frequency density
What is important to consider when calculating class width?
Some intervals may not include the entire bar
What formula is used to work out the frequency for each bar?
FD X CW = F
What must be the same when comparing histograms?
Class intervals and frequency density scales
What should be described when comparing histograms?
The shape of the distribution and what it shows
What are the possible shapes of a distribution?
Positive, negative, or symmetrical
What are frequency polygons similar to?
Histograms with equal class widths but without bars
How are points plotted in a frequency polygon?
Using mid-points of class intervals, then joined with straight lines
What common error involves midpoints in frequency polygons?
Midpoints not used
What is a common error in connecting points in frequency polygons?
Points not joined together with straight lines but with a curve instead
What can make diagrams misleading?
Shape, axes, and scales
What is a type of misleading diagram that uses the same symbol and size?
Pictograms
What is a drawback of 3D charts?
They distort parts of the diagram
How can colors make diagrams misleading?
Some colors may make parts stand out more, appearing more important
What can happen if lines in a diagram are drawn too thick?
It becomes difficult to read information
What is a misleading aspect of scales in diagrams?
Scales that do not start at zero
What is another issue with axes in diagrams?
Axes that are unevenly scaled
What is a common issue with axes that can mislead readers?
Axes that are not labelled
Fill in the blank: Diagrams should use a _______ for clarity.
key
