The goal of this activity is for students to learn how to calculate standard deviation ( or ) using technology. Standard deviation is a measure of variability. The work in this activity prepares students to be successful in a future Algebra 1 lesson when they have to calculate the standard deviation of data sets. 

The purpose of this discussion is to clarify how to calculate standard deviation using technology and how to interpret the standard deviation in these situations. Select students to share their solutions. Ask students how the standard deviation influenced their preferred movie and restaurants.

The goal of this activity is for students to practice the skill of comparing data sets by comparing standard deviations. Previously, students discovered the importance of variability in comparing data sets when they chose the better choice first, then calculated the standard deviation and reflected on whether or not variability was a factor in their decisions. This activity gives students the opportunity to calculate the standard deviation and use it to inform their decisions first. Students reason abstractly and quantitatively (MP2) when they use appropriate statistics for a situation to decide a better option.

Select students to share the route they chose, including their reasons. The purpose of the discussion is to relate standard deviation to variability and discuss how that is related to consistency in many situations.

If no one mentions it, point out that the mean travel time is 24 minutes for both routes, so the recommendation should be made on the basis of variability.