Lecture 11 - Interpreting Graphs

Pie charts categorical variable. side note bar charts also deal with categorical variables

great for displaying relative frequencies (proportion or percentage)

• Not great for displaying absolute frequencies 

• The raw count of how many times a value or category appears

Histograms

distribution of a numerical variable

Gives you a visual, intuitive sense of the mean, range, skew, and potential outliers

Scatterplots and line graphs

show you how 2 numerical variables are associated

Line graphs

• X-axis: Usually as a discrete variable

• Y-axis: A continuous variable you care about

Inferential statistics

allow researchers to draw conclusions about a population based on data from a sample (generalizations)

Descriptive statistics

They describe characteristics of a sample or population but don't make predictions or generalizations to larger groups