Graphical Displays Flashcards
Bar graphs are commonly used to…
Compare the sizes of categories
Dot plots are useful with regard to….
Categorical (qualitative) variables
Data for bar graphs is measured in….
Percents or frequencies
Relative frequencies are used when…
Comparing distributions of different size populations
Three keys to describing a distribution:
- Shape
- Center
- Spread
Ways to display quantitative data:
Histograms
Cumulative relative frequency plots (ogives)
Stemplots
In a histogram, relative area corresponds to…
Relative frequency
Stemplots
Give exact values, unlike most histograms
The center
Separates values roughly in half
Spread
Scope of values from smallest to largest
Clusters show…
Natural subgroups
Gals show….
Holes where no values fall
Extreme values are called…..
Outliers
Modes
Values with peaks above them
Symmetric distribution
One in which the two halves are mirror images of each other
Distribution skewed right
Spreads far and thinly toward higher values
Has a cumulative frequency out that rises steeply at first and then slows later
Distribution skewed left
Spreads far and thinly toward lower values
Has a cumulative frequency out that rises slowly at first and then steeply later
Bell-shaped distribution
Is symmetric with a center mound and two sloping tails
A distribution is uniform is….
Its histogram is a horizontal line
Cumulative relative frequency plot
Visually show sum frequencies
Both dotplots and stem plots can show…
Symmetry
Gaps
Clusters
Outliers
All normal curves are…
Bell-shaped and symmetric
*but not all bell-shaped and symmetric curves are normal
Households incomes and home proves tend to be..,
Skewed right
