Math 111 - Week 4 Notes

Mon, Feb 7

Today we started talking about data and variables. We looked at two example data tables:

1. Our class data
2. NTHSA data on motor vehicle deaths in the U.S.

Each column in a data table corresponds to a variable and each row represents one individual. Variables that are numbers are quantitative and variables that are words are categorical.

We finished by asking the following questions:

1. Why is it better to look at Fatalites per 100,000 Population than just Total Fatalities if you want to compare traffic safety in different years?

2. If you want to see if driving has gotten safer in the last 20 years, which is the best variable to look at?

   • Total fatalities
   • Fatalities per 100,000 people
   • Fatalities per 100 million VMT

Wed, Feb 9

Today we talked about the best ways to graph data.

• For a categorical variable, the best way is usually a bar chart.
  
• For a quantitative variable, the best option is either a histogram or a box-and-whisker plot.

We focused on histograms, and did this workshop:

• Histograms workshop

You can read more about this material in the Describing Data section of the textbook.

Fri, Feb 11

Today we talked about the five-number summary and box-and-whisker plots (also known as boxplots).

• Boxplots Workshop