Visualizing Data Flashcards
Individuals
Simplest kind of information. Hold properties called variables. They can be cases, things, people, etc.
Variable
A property of an individual, like the height (variable) of a person (individual). (The stuff that goes in the middle of a data table.
Data Table
When we organize data into a table.
Data
Individuals and variables.
Data are individual facts, statistics, or items of information, often numeric. In a more technical sense, data are a set of values of qualitative or quantitative variables about one or more persons or objects, while a datum is a single value of a single variable.
Categorical vs Quantitative variables.
Quantitative are numerical variables.
Categorical are descriptive, non-numerical attributes. Categorical are words, not numbers (also called qualitative variables).
Discrete variable
Those that we can obtain by counting full numbers or integers. A scoop of icecream wouldn’t be counted as 1.4 scoops of icecream.
Quantitative Variables
Include data as decimals, fractions, or irrational numbers.
4 levels of measurement (scales)
Nominal, ordinal, interval and ratio.
Nominal Scale
Things like food, colors, names and “yes” or “no”. Only categorical ata can be measured with a nominal scale.
Ordinal scale
Data that can be ordered from best to worst (awesome, good, satisfactory or terrible). She mentions top three national parks.
Interval scale
Can be ordered like ordinal data, but there is a known interval between measurements. For example temperature (50-60 degrees).
Ratio Scale
Just like interval except that ratio scale data has a starting point or absolute zero. Temperature (interval) can be negative but things like time, height and weight are ratio scale can because they can never be negative.
Constructing a table
Usually you’ll put the individuals listed on the left hand side and the variables listed across the top. But when you have a lot of variables and a few individuals you may want to list the individuals across the top.
Bar graph/Bar chart
One of the simplest ways to summarize and represent data.
Pie Chart
A pie chart (or a circle chart) is a circular statistical graphic, which is divided into slices to illustrate numerical proportion.
Frequency table
Table that shows the frequency count of each individual (I think she also calls it a summary table).
Bar graph
Great for showing multiple variables for the same individuals side by side.
Here the continents are individuals and the count is a quantitative variable. Often bar graphs tend to be created in order from highest to lowest (usually when the order is not important like with time).
Line Graphs
Similar to bar graphs (you can turn a bar graph into a line graph by drawing a straight line through the tops of the graph). Line graphs are best used to show changes over time or a connection between individuals.
Ogive
A special kind of line graph. Looks like a line graph but accumulates the data (an accumulated line graph). Not good for temperatures (temperatures don’t accumulate), but good for accumulated annual savings.
Two way tables
Constructed from data that’s dependent on two categorical variables. Sometimes this kind of data has independent and dependent variables. In a one way table we have one independent variable (individuals). In a two way table we have two independent categorias on which the variables are dependent. Two way tables can be represneted as line graphs or barcharts (also some more revealing comparison bar graphs and comparison line graphs).
Comparison bar graph
Illustrates the variables side-by-side color coded for each year.
Comparison Line Graph
Depicts the data as lines compared year by year, color coded and with a legend.
Venn Diagrams
Way to express two way table data using overlapping circles indicating conditions that were met (either sprinkles, frosting or both). **The number in the outside box represents data that doesn’t meet any of the conditions. (no sprinkles or frosting).**
It can be different size circles and it can be more than two circles.
