AP Statistics: Dotplots, Describing Shape, Comparing Distributions, Stemplots, Histograms Dotplots

Center

Where the data appears to cluster

Comparing centers

Data A appears to center around # to #/# whereas Data B has a higher/lower center around # to #/#

Spread

What is the range (highest value-lowest value)? IQR (Q3-Q1)? Which data appears more spread out and less consistent.

Comparing Spread

Data A has a range/IQR of # whereas Data B has a smaller/larger spread with a range/IQR of #

Shape

Bell-shaped? symmetric? bimodal? skew right or left?

Comparing Shapes

Data A appears to be approximately normal/skew right/skew left with the left/right side of the curve/box being larger/smaller/symmetrical whereas Data B appears to be approximately normal/skew right/skew left with the left/right side of the curve/box being larger/smaller/symmetrical

Gaps and outliers

Note whether or not any data appears to be an outlier and what gap made that outlier

Comparing Gaps and Outliers

Data A appears to have a gap between # and # and outlier(s) #,#… on the upper/lower end of the data while Data B appears to have a gap between # and # and outlier(s) #,#… on the upper/lower end of the data

How to make stemplots

Label stem and leaf with title of data (w/ context), Create a key (ex. 4|6-= 46), Make a vertical list starting with the lowest value in the data as your stem, ending with the highest value, including numbers not present in the data to show gaps. Make a line to the right/left of the vertical list and fill in leaves with a proper scale (don't squish)

Histograms

Display quantitative data by dividing data into intervals