2: Describing Data, Part 1
2: Describing Data, Part 1Objectives
 Compute and interpret a basic proportion/risk/probability and odds
 Select and interpret the appropriate visual representations for one categorical variable, two categorical variables, and one quantitative variable
 Use Minitab to construct frequency tables, pie charts, bar charts, twoway tables, clustered bar charts, histograms, and dotplots
 Compute and interpret complements, intersections, unions, and conditional probabilities given a twoway table
 Identify outliers on a histogram or dotplot
 Interpret the shape of a distribution
 Compute and interpret the mean, median, mode, and standard deviation
 Compute and interpret percentiles and z scores
 Apply the Empirical Rule
 Interpret a five number summary
This lesson corresponds to Sections 2.12.3, and P.1 in the Lock^{5} textbook.
Recall from Lesson 1 that variables can be classified as categorical or quantitative:
 Categorical
 Names or labels (i.e., categories) with no logical order or with a logical order but inconsistent differences between groups, also known as qualitative.
 Quantitative
 Numerical values with magnitudes that can be placed in a meaningful order with consistent intervals, also known as numerical.
The graphs, descriptive statistics, and inferential statistics that are appropriate depending on the nature of the variable(s) in a given scenario. Before beginning this lesson, you should be able to classify variables as categorical or quantitative. If you are having difficulties with this, go back to review Lesson 1 or speak with your instructor.
2.1  Categorical Variables
2.1  Categorical VariablesCategorical variables are discussed in Sections 2.1 and P.1 of the Lock5 textbook.
Variables can be classified as categorical or quantitative. In this section of the lesson, we will be focusing on categorical variables. Categorical variables are those that provide groupings that may have no logical order, or a logical order with inconsistent difference between groups (e.g., the difference between 1 and 2 is not equivalent to the difference between 3 and 4).
This course includes many examples and practice problems for you. Many of these will apply the concepts that we learn to experiments involving rolling a die or randomly selecting a card from a standard 52card deck. If you are unfamiliar with either of these, take a moment here to review.
 Die

A standard die has 6 sides: 1, 2, 3, 4, 5, 6
 52Card Deck

A standard 52card deck of playing cards has 13 Hearts, 13 Diamonds, 13 Spades, and 13 Clubs. Hearts (â™¥) and Diamonds (â™¦) are red suits. Spades (â™ ) and Clubs (â™£) are black suits. For each suit, there is a 2, 3, 4, 5, 6, 7, 8, 9, 10, Jack, Queen, King, and Ace. Jacks, Queens, and Kings are "face cards."