A quantitative variable is one for which mathematical operations make sense Response time is a good quantitative variable Quantitative variables will often be measured in experiments Categorical variables Define groups or classes in the data Gender or Year in college are good categorical variables Categorical variables often correspond to things manipulated in experiments. The difficult thing about analyzing data is that not all of the data is the same. Sorting the data can help The data may look different when sorted. Still, there seem to be a lot of numbers here. It is often helpful to graph the data in some way.
Humans are visual creatures.
Patterns become evident in graphs. The spread of the numbers is a distribution. Think about what is possible Think about how likely the possibilities are. Qualities of Distributions to keep in mind. The stemplot is good for looking at a small set of numbers.