Instructional and practice activities in this section are designed to help students

1. Visualize data about two or more groups in frequency plots (dot plot, box and whisker plot, or histogram)

2. Make a decision about whether or not the two groups are the same or different based on their data distributions (range, shape of distribution, and measure(s) of center (mean, median or modes).

Examples:

1. Did the fleets of Toyotas and Chevrolets made between 2002 and 2011 the same or different in fuel efficiency?

[insert figure]

2. How do smoking rates in New Hampshire and Maine compare?

[insert figure]

Bar graphs can be used to compare *summary values* of two groups, but because the bars don't show the range of the data for each group (i.e. how much the data varies in each group) it is not reasonable to decide if two groups are meaningfully different based on bar graphs alone (unless range or error bars are drawn).

[insert figures]

3. Describe the magnitudes of earthquakes in Japan, Alaska, and California. Are all three regions the same in the strength of earthquakes they experience?