1. Sudoku is a puzzle consisting of squares arranged in 9 rows and 9 columns. The 81 squares are further divided into nine 33 square boxes. The object is to fill in the squares with numerals 1 through 9 so that each column, row, and box contains all nine numbers. However, there is a requirement that each number appear only once in any row, column, or box. Each puzzle already has numbers in some of the squares. Would it be appropriate to use a random-number table to select a digit for each blank square? Explain.
2. A brief survey regarding opinions about recycling was carefully designed so that the wording of the questions would not influence the responses. Jill administered the survey at a farmer's market. She approached adults and asked if they would fill out the survey, explaining that the results might be used to set trash collection and recycling policy in the city. She stood by silently while the form was filled out. Jill was wearing a green T-shirt with the slogan "fight global warming." Are the respondents a random sample of people in the community? Are there any concerns that Jill might have influenced the respondents?
3. How are dot plots and stem-and-leaf displays similar? How are they different?
4. How long did real cowboys live? One answer may be found in the book The Last Cowboys by Connie Brooks (University of New Mexico Press). This delightful book presents a thoughtful sociological study of cowboys in West Texas and southeastern New Mexico around the year 1890. A sample of 32 cowboys gave the following years of longevity:

58	52	68	86	72	66	97	89	84	91	91
92	66	68	87	86	73	61	70	75	72	73
85	84	90	57	77	76	84	93	58	47

• Make a stem-and-leaf display for these data.
• Interpretation: Consider the following quote from Baron von Richthofen in his Cattle Raising on the Plains of North America: "Cowboys are to be found among the sons of the best families. The truth is probably that most were not a drunken, gambling lot, quick to draw and fire their pistols." Does the data distribution of longevity lend credence to this quote?

5. Consider the following Minitab display of two data sets:

Variable	N	Mean	SE Mean	StDev	Minimum	Q1	Median	Q3	Maximum
C1	20	20	1.62	7.26	7	15	20	25	31
C2	20	20	1.3	5.79	7	20	22	22	31

• What are the respective means? the respective ranges?
• Which data set seems more symmetric? Why?
• Compare the interquartile ranges of the two sets. How do the middle halves of the data sets compare?

6. "Radon: The Problem No One Wants to Face" is the title of an article appearing in Consumer Reports. Radon is a gas emitted from the ground that can collect in houses and buildings. At certain levels, it can cause lung cancer. Radon concentrations are measured in picocuries per liter (pCi/L). A radon level of 4 pCi/L is considered "acceptable." Radon levels in a house vary from week to week. In one house, a sample of 8 weeks had the following readings for radon level (in pCi/L):

1.9

2.8

5.7

4.2

1.9

8.6

3.9

7.2

• Find the mean, median, and mode.
• Find the sample standard deviation, coefficient of variation, and range.
• Interpretation: Based on the data, would you recommend radon mitigation in this house? Explain.