Unit 1, Lesson 13

Standard Deviation in Real-World Contexts

Extra Support Materials for Algebra 1

13.1

Warm-up

The runner is running a marathon.

13.2

Movie A ratings on a 10-point scale:

9, 8, 10, 10, 7, 1, 8, 1, 2, 8

Movie B ratings on a 10-point scale:

9, 8, 8, 7, 9, 7, 7, 9, 7, 8

Restaurant A ratings on a 100-point scale:

88, 87, 89, 90, 87, 85, 88, 91, 86, 86, 88, 89

Restaurant B ratings on a 100-point scale:

90, 65, 89, 50, 94, 93, 95, 95, 75, 70, 88, 89

Calculate the mean and standard deviation for each data set.
Considering these statistics, which movie and restaurant would you choose? Explain your reasoning.

13.3

Priya times the ride from home to school on two different routes.
Here are the times in minutes:

Route A: 21.5, 23, 24, 25, 26.5

Route B: 12, 20, 24, 28, 36

Before calculating the standard deviation, predict which route has a greater standard deviation. Explain your reasoning.
Calculate the standard deviation, and use it to decide which route you would recommend for Priya.

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