1. Identify the population and the sample in the following study.
A study of 163 patients with sleep disorders was conducted to find a link between obesity and sleep disorders. (Source:Archives of Internal Medicine 1998)
2. Determine whether the numerical value is a parameter or a statistic.
(a) In a survey of a sample of parents, 53% said they protect their children from sun exposure using sunscreen. (Source: Morbidity and Mortality Weekly Report)
(b) In a union’s vote, 67% of all union members voted to ratify a contract proposal.
3. Determine whether the data are qualitative or quantitative.
(a) A database of student identification numbers
(b) The test scores in a statistics class
6. Identify which sampling technique was used in each study. Explain your reasoning.
(a) A journalist goes to a beach to ask people how they feel about water pollution
(b) For quality assurance, every fifth engine part is selected from an assembly line and tested for durability.
(c) A study on attitudes about smoking is conducted at a college. The students are divided by class (freshman, sophomore, junior, and senior). Then a random sample is selected from each class and interviewed.
7. Which sampling technique used in Exercise 6 could lead to a biased study?
8. Determine whether each statement is true or false. If it is false, rewrite it as a true statement.
(a) A parameter is a numerical measure that describes a sample characteristic.
(b) Ordinal data represent the highest level of measurement.
p. 6-7 #9-12, 17-20
In Exercises 9–12, determine whether the data set is a population or a sample. Explain your reasoning.
9. The age of each state governor
10. The speed of every fifth car passing a police speed trap
11. A survey of 500 students from a university with 2000 students
12. The annual salary for each employee at a company
In Exercises 17–20, identify the population and the sample.
17. A study of 33,043 infants in Italy was conducted to find a link between a heart rhythm abnormality and sudden infant death syndrome. (Source: New England Journal of Medicine)
18. A survey of 1023 households in the U.S. found that 65% subscribe to cable television
19. A survey of 546 women found that more than 56% are the primary investor in their household. (Adapted from: Roper Starch Worldwide for Intuit)
20. A survey of 872 vacationers from the U.S. found that they planned on spending at least $1800 for their next vacation
p. 107 Chapter Quiz #3-7
3. U.S. sporting goods sales (in billions of dollars) can be classified in four areas: clothing (9.6), footwear (5.9), equipment (13.5), and recreational transport (15.1). Display the data using (a) a pie chart and (b) a Pareto chart. (Source: National Sporting Goods Association)
4. Weekly salaries (in dollars) for a sample of registered nurses are listed.
774 446 1019 795 908 667 444 960
a) Find the mean, the median, and the mode of the salaries. Which best
describes a typical salary?
b) Find the range, variance, and standard deviation of the data set. Interpret
the results in the context of the real-life setting
5. The mean price of new homes from a sample of houses is $155,000 with a
standard deviation of $15,000. The data set has a bell-shaped distribution.
Between what two prices do 95% of the houses fall?
6. Refer to the sample statistics of Exercise 5 and use z-scores to determine
which, if any, of the following house prices is unusual
7. The number of wins for each Major League Baseball team in 2000 are listed.
(Source: Major League Baseball)
87 85 83 74 69 95 90 79 77 69 91 91 82 71 95
94 79 67 65 95 85 73 72 69 65 97 86 85 82 76
a) Find the quartiles of the data set.
65 65 67 69 69 69 71 72 73 74 76 77 79 79 82 82 83 85 85 85 86 87 90 91 91 94 95 95 95 97
3. The midpoint of a class is the sum of its lower and upper limits
4. The relative frequency of a class is the sample size divided by the frequency of the class
19. Use a dot plot to display the data. The data represent the life span (in days) of 40 houseflies.
20. Use a pie chart to display the data. The data represent the number of Nobel Prize laureates by country during the years 1901–1993
Japan’s estimated population for the year 2010 is given in the bar graph. Make a frequency distribution for the data. Then use the table to estimate the sample mean and the sample standard deviation of the data set. (Source: U.S. Census Bureau, International Data Base)
The coefficient of variation CV describes the standard deviation as a percent of the mean. Because it has no units, you can use the coefficient of variation to compare data with different units
(a) Use the shortcut formula to calculate the sample standard deviation for the data set given in Exercise 19
(b) Compare your results to those obtained in Exercise