Statistics
Graphical Summaries of one Variable
September 9, 2008
Reading Quiz
1. A dataset has individuals and variables. A variable is a
2. Yesterday we collected some data from each student. Of the following, circle the categorical variables.
Writing Hand
Gender
Cash
Sleep
3. Makeup tests are available for those who miss class.
Random letter
T
Speed
F
Outline
1. The distribution of a variable
2. Summarizing the distribution of a categorical variable
3. A histogram summarizes graphically the distribution of a quantitative variable.
4. Constructing a histogram.
5. What does a histogram tell us about the distribution?
(a) the pattern (shape, center, spread)
(b) deviations from the pattern (outliers)
6. Words describing shape
unimodal, bimodal, etc.
symmetric, skewed to the left, skewed to the right
7. stemplot (stem-and-leaf plot)
Statistics
Graphical Summaries of one Variable
Screenshots of Crunchit menus
1. Reading a file.
2. Tables, barcharts, pie charts.
3. Histograms, stemplots
September 9, 2008