Lesson 2: Describing Data, Part 1

Objectives

Upon successful completion of this lesson, you will be able to:

  • 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 Express to construct frequency tables, pie charts, bar charts, two-way tables, clustered bar charts, histograms, and dotplots
  • Compute and interpret complements, intersections, unions, and conditional probabilities given a two-way 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 2.1-2.3, and P.1 in the Lock5 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.