IB Math Analysis

Group Members:

Activity 2B: Web Sudoku

The purpose of this activity is to explore z-scores and percentiles and how they tell about the location of an observation under a density curve. Go to www.websudoku.com to see a Sudoku puzzle (you may use your phone or your Mac Book). While relaxing one day, Price played a game of Web Sudoku. When he finished, the following display appeared on his computer screen.

1. The density curve in the display was based on four million puzzles solved in one week at this Web site. Describe the shape of the above distribution of solution times. Explain why the shape of the distribution is what it is.

2.  How did Price do? Use percentiles, standardized values (z-scores), and raw data to help answer this question.

3.  Elsewhere on this website, Price found the following statement: “The Average shown is the median rather than the mean, since the time distribution is positively skewed.” Explain why they would state this and what it means.

4.  Each group member will play one game of Sudoku on the easy setting. Record the time it takes each group member to finish the puzzle in the space below. Remember to press the “How am I doing?” button to finish the game.

5.  Confer with the other groups and record their times as well in the space below.

6.  Calculate and record the mean, median, and standard deviation time for the entire class. You may want to use minutes with decimals or just do all seconds to make it easier.

7.  Calculate and record everyone’s z-score and percentile for the entire class. Use the back of this paper if you need more room.

8.  Were their any z-scores that stood out to you as being particularly “unusual”? If so, which one(s) and why?

9.  Calculate the z-score if someone were to score at the 50th percentile.

10.  Calculate the z-score if someone were to score at the 16th percentile (Hint: think about the 68-95-99.7 rule).

11.  Calculate the z-score if someone were to score at the 84th percentile (Hint: think about the 68-95-99.7 rule).

12.  Write at least 2 sentences telling about or explaining something that you learned from completing this activity.