Use videos and/or book (Chapter 5 to page 111) to review the Dan Schuster Notes (or create your own) and practice problems. Come to class with questions on concepts so we can start practicing on additional problems. The Density Curve in Dan's notes is not covered in the chapter in the book.
Practice Problems:
1. (Video 1) The table gives the mean and standard deviation of reaction times (in seconds) for each of two different stimuli. Suppose your reaction time is 4.2 seconds for the first stimulus and 1.8 seconds for the second stimulus. Compared to other people, to which stimulus are your reacting more quickly? (HINT: You actually want the most negative Z score because you want to be lower than the average.) (Answer: Stimulus 2)
2. (Video 2) In a study investigating the effect of car speed on accident severity, the vehicle speed at impact was recorded for 5,000 fatal accidents. The mean speed was 42 mph and the standard deviation was 15 mph.
What was the range of the vehicle speeds for the 68% of data centered around the mean? (Answer: 27 to 57 mph)
What was the range of the vehicle speeds for 95% of the data centered about the mean? (Answer: 12 to 72 mph)
What was the range of the vehicle speeds for 99.7% of the data centered about the mean? (Answer: 0 to 87 mph)
3 VIDEOS
Video 1: Calculating Z-Scores
Video 2: The Empirical Rule (68-95-97.5 Rule)
Video 3: Shifting and Scaling Data
Play with the applet that I used in this video that lets you shift and scale data.