In December 2011, Consumer Reports published their study of labeling of seafood sold in New York, New Jersey, and Connecticut. They purchased 190 pieces of seafood from various kinds of food stores and restaurants in the three states and genetically compared the pieces to standard gene fragments that can identify the species. Laboratory results indicated that 22% of these packages of seafood were mislabeled, incompletely labeled, or misidentified by store or restaurant employees. a) Construct a 95% confidence interval for the proportion of all seafood packages in those three states that are mislabeled or misidentified. b) Explain what your confidence interval says about seafood sold in these three states. c) A 2009 report by the Government Accountability Board says that the Food and Drug Administration has spent very little time recently looking for seafood fraud. Suppose an official said, "That's only 190 packages out of the billions of pieces of seafood sold in a year. With the small number tested, I don't know that one would want to change one's buying habits." (An official was quoted similarly in a different but similar context). Is this argument valid? Explain.

In December 2011, Consumer Reports published their study of labeling of seafood sold in New York, New Jersey, and Connecticut. They purchased 190 pieces of seafood from various kinds of food stores and restaurants in the three states and genetically compared the pieces to standard gene fragments that can identify the species. Laboratory results indicated that 22% of these packages of seafood were mislabeled, incompletely labeled, or misidentified by store or restaurant employees.

a. Construct a 95% confidence interval for the proportion of all seafood packages in those three states that are mislabeled or misidentified.

b. Explain what your confidence interval says about seafood sold in these three states.

c. A 2009 report by the Government Accountability Board says that the Food and Drug Administration has spent very little time recently looking for seafood fraud. Suppose an official said, "That's only 190 packages out of the billions of pieces of seafood sold in a year. With the small number tested. I don't know that one would want to change one's buying habits." (An official was quoted similarly in a different but similar context). Is this argument valid? Explain.

Several factors are involved in the creation of a confidence interval. Among them are the sample size, the level of confidence, and the margin of error. Which statements are true?

For a given sample size, higher confidence means a smaller mar gin of error.

In a national poll taken in February 2008, Gallup asked 1006 adults whether they were baseball fans; 43% said they were. Two months previously, in December 2007, 40% of a similar-size sample had reported being baseball fans. Find the margin of error for the 2008 poll if we want 90% confidence in our estimate of the percent of national adults who are baseball fans.

In December 2011, Consumer Reports published their study of labeling of seafood sold in New York, New Jersey, and Connecticut. They purchased 190 pieces of seafood from various kinds of food stores and restaurants in the three states and genetically compared the pieces to standard gene fragments that can identify the species. Laboratory results indicated that 22% of these packages of seafood were mislabeled, incompletely labeled, or misidentified by store or restaurant employees. A 2009 report by the Government Accountability Board says that the Food and Drug Administration has spent very little time recently looking for seafood fraud. Suppose an official said, "That's only 190 packages out of the billions of pieces of seafood sold in a year. With the small number tested, I don't know that one would want to change one's buying habits." (An official was quoted similarly in a different but similar context). Is this argument valid? Explain.

Choose the best answer. The five-number summary for a data set is given by min = 5,

$$Q_1 = 18,$$

median = 20,

$$Q_3 = 40,$$

max = 75. If you wanted to construct a boxplot for the data set (that is, one that would show outliers, if any existed), what would be the maximum possible length of the right-side "whisker"? (a) 33 (b) 35 (c) 45 (d) 53 (e) 55

The December 2011 Consumer Reports study described in the earlier exercise also found that 12 of the 22 "red snapper" packages tested were a different kind of fish.$\newline$ Construct a 95% confidence interval.

Consumer Reports purchased samples of chicken offered for sale in 23 states and checked them for bacterial contamination. The magazine found that 81% of the packages were contaminated with campylobacter, 15% with salmonella, and 13% with both. What's the probability that a package of chicken was bacteria-free?

In December 2011, Consumer Reports published their study of labeling of seafood sold in New York, New Jersey, and Connecticut. They purchased 190 pieces of seafood from various kinds of food stores and restaurants in the three states and genetically compared the pieces to standard gene fragments that can identify the species. Laboratory results indicated that 22% of these packages of seafood were mislabeled, incompletely labeled, or misidentified by store or restaurant employees. Explain what your confidence interval says about seafood sold in these three states.

A TV newscaster reports the result of a poll of voters, and then says, "The margin of error is plus or minus 4%." Explain carefully what that mean.

For each situation described below, identify the population and the sample, explain what p and p

$$\hat { p }$$

represent, and tell whether the method s of this chapter can be used to create a confidence interval. A school is considering requiring students to wear uniforms. The PTA surveys parent opinion by sending a questionnaire home with all 1245 students; 380 surveys are returned, with 228 families in favor of the change.

A company is criticized because only 13 of 43 people in executive-level positions are women. The company explains that although this proportion is lower than it might wish, it's not a surprising value given that only 40% of all its employees are women. What do you think? Test an appropriate hypothesis and state your conclusion. Be sure the appropriate assumptions and conditions are satisfied before you proceed.

The Paralyzed Veterans of America is a philanthropic organization that relies on contributions. They send free mailing labels and greeting cards to potential donors on their list and ask for a voluntary contribution. To test a new campaign, they recently sent letters to a random sample of 100,000 potential donors and received 4781 donations. Give a 95% confidence interval for the true proportion of their entire mailing list who may donate.

In January 2002, two students made worldwide headlines by spinning a Belgian euro 250 times and getting 140 heads- that's 56%. That makes the 90% confidence interval (51%, 61%). What does this mean? Are these conclusions correct? Explain.

Between 51% and 61% of all euro s are unfair.