Lecture 12: Bar Plots And Line Plots Flashcards
Bar plots are also known as
Bar graphs
Bar plots (graphs) are useful and are a common way to visualize?
Mean comparisons
The top of each bar in a bar plot shows what in the given condition/group
The sample mean/sample statistic of interest
Be careful cause sometimes the visual differences can be misleading and it depends on the ________ range
Y-axis
For ratio-scale variables we want the y-axis to start from ____ so that the relative sizes of the bars correspond to the relative quantities
Zero
Heights of the bars are usually _______ so they aren’t that meaningful in themselves without knowing the _______ _____
Estimates
Standard error
What do we put on top of bars to indicate the size of the standard error?
Error bars!
Error bars don’t always represent standard errors. Sometimes they represent: (2)
So we should always include a _____ so that the reader knows how to interpret them
- Confidence intervals
- Standard deviations
Note
Sometimes different bars are different colors and can be useful in some cases. Name an example
When there are many graphs that all use the same color scheme!
Unnecessary fancy distractions in a graph is called:
“Chart junk”
Line plots are also known as
Line graphs
Line plots are typically used for ____ ____ data
Time series data
Time series data
Data collected when taking repeated measurements at different time points
To plot a line graph how do you do it?
- Plot individual points
- Connect the points with line segments
To emphasize the direction change from one time to the next
The x-axis variable in a line plot can be some other quantitative variable besides time eg.
Dosage of a drug
Do line segments between points represent data?
Nope - they just indicate direction of change between two points
Is it useful to include error bars in line graphs?
YES!
Whats the best approach to plot data points in line graphs?
Showing all individual measurements as points instead of only showing the means! —> it provides much more information
