=+13. Speeds of cars were measured as they passed one point on a road to study whether traffic speed controls were needed. Here’s a histogram and normal probability plot of the measured speeds. Is a Normal model appropriate for these data? Explain.

Exercises M07_SHAR8696_03_SE_C07.indd 262 14/07/14 7:31 AM Exercises 263 15.0 22.5 20 15 10 5

30.0

# of cars Speed (mph)

–1.25 0 1.25 Nscores 32 28 24 20 Speed (mph)