1. AP Statistics CH. 4 Displaying Quantitative Data
By. Jamie Morreale and Thulasi Thiviyanathan

2. What is a Histogram? Histograms plot the bin counts
as the height of bars
The bins and the counts in each
bin give the distribution of the
quantitative variable
Relative Frequency Histogram- displays
the percentage of cases in each bin
instead of the count

3. How to make a Histogram •Used with numerical data •The Bars touch
•There are two types
–Discrete-bars which are centered over discrete values
–Continuous-bars cover a class (interval) of values

4. What is a Stem-and-Leaf Display?
Stem-and-leaf displays- contain all the information found in a histogram and, when carefully drawn, satisfy the area principle and show the distribution. In addition, stem-and-leaf displays preserve the individual data values.

5. What are Dotplots?
Dotplot is a simple display. It just places a dot along an axis for each case in the data
They may be displayed vertically or horizontally

6. CUSS Center Unusual Points Shape Spread
Use CUSS when describing a distribution.

7. Humps and Bumps
Identify if the Histogram has a single, central, or several humps.
Modes are humps
Unimodal- a histogram with one main peak
Bimodal- histograms with two peaks
Multimodal- histograms with three or more peaks
Uniform- a histogram distribution that is roughly flat

8. Symmetry Identify if the Histogram is Symmetric
Tails- are the parts that typically trail off on either side. They can be identified as having long tails or short tails.
Skewed- a distribution is skewed if it’s not symmetric and one tail stretches out farther than the other.
Skewed Left- when the longer tail stretches to the left
Skewed Right- when the longer tail stretches to the right

9. Unusual
Outliers- extreme values that don’t appear to belong with the rest of the data. They may be unusual values that deserve further investigation. or just mistakes.

10. Compare the graphs Compare the two graphs on the number of
male and female patients

11. What is a timeplot?
Timeplot- displays data that change over time. Often, successive values are connected with lines to show trends more clearly.

12. What can go Wrong? Don’t make a histogram of a categorical variable
Don’t look for shape, center, and spread of a bar chart
Don’t use bars in every display- save them for histograms and bar charts
Choose a bin width appropriate to the data
Avoid inconsistent scales
Label Clearly

13. HW Problem #35 3 7 44 45
222 10 01 98 8
777 2 11
999888 1
77776 67
According to the data U.S. car milage have a lower center and is skewed to the right. The mode is near 19 mpg. Others have more cars in their category with a mode at 32 mpg and another mode at 22 mpg.
U.S. Cars
Others
1 l 6 means 16 mpg

14. HW Problem #37 8
0148 7 9 6
02 3 5 4 3 25 2
The graph is skewed to the left and also has some gaps.
According to the timeplot, the cost is generally increasing overtime.
2 l 8 means $28 thousand/mW