1. Unit 4: Describing Data
After 8 long weeks, we have finally finished Unit 3: Linear & Exponential Functions. Now on to Unit 4 which will last 3 weeks (yes we will finish the week we get back from Thanksgiving). This unit is all about statistics, so let’s begin by getting to know some of the vocabulary of statistics…

2. Vocabulary: Box-and-Whisker Plot (Box Plot) Center Dot plot
First Quartile
Histogram
Interquartile Range
Mean Absolute Deviation
Outlier
Second Quartile (Q2)
Shape
Symmetry
Number of Peaks
Direction of Skew
Uniformity
Spread
Third quartile
Trend
Association
Bivariate data
Categorical variables
Causation
Conditional Relative Frequencies
Correlation Coefficient
Joint Frequencies
Line of best fit
Marginal Frequencies
Quantitative Variables
Residuals
Scatter plot
Two-frequency table

3. Learning Target:
Students can identify the best way to represent, compare, and interpret sets of data.
Standard: MCC9-12.S.ID.1-3, 5-9, SP.5

4. Box Plot
A plot showing the minimum, maximum, first quartile, median, and third quartile of a data set; the middle 50% of the data is indicated by a box. Example:

5. Box Plot: Pros and Cons Advantages: Shows 5-point summary and outliers
Easily compares two or more data sets
Handles extremely large data sets easily
Disadvantages:
Not as visually appealing as other graphs
Exact values not retained

6. Dot Plot
A frequency plot that shows the number of times a response occurred in a data set, where each data value is represented by a dot.
Example:

7. Dot Plot: Pros and Cons Advantages: Simple to make
Shows each individual data point
Disadvantages:
Can be time consuming with lots of data points to make
Have to count to get exact total. Fractions of units are hard to display.

8. Histogram
A frequency plot that shows the number of times a response or range of responses occurred in a data set.
Example:

9. Histogram: Pros and Cons
Advantages:
Visually strong
Good for determining the shape of the data
Disadvantages:
Cannot read exact values because data is grouped into categories
More difficult to compare two data sets

10. Histogram vs. Bar Graph
Histograms are a great way to show results of continuous data, such as:
weight
height
how much time
etc.
But if your data is in categories (such as Country or Favorite Movie), then you should use a Bar Graph