Statistics Through Applications 2nd Edition solutions

Statistics Through Applications 2
Dead trees On the west side of Rocky Mountain National Park, many mature pine trees are dying due to infestation by pine beetles. Scientists would like to use sampling to estimate the proportion of all pine trees in the area that have been infected. (a) Explain why it wouldnt be practical for scienti

Statistics Through Applications 2
Domain names When it comes to Internet domain names, is shorter better? According to one ranking of Web sites in 2008, the top 8 sites (by number of hits) were yahoo.com, google.com, youtube.com, live.com, msn.com, myspace.com, wikipedia.org, and facebook.com. Th ese familiar sites certainly have sho

Statistics Through Applications 2
Looking for metal A boy uses a homemade metal detector to look for valuable metal objects on a beach. Th e machine isnt perfectit identifi es only 98% of the metal objects over which it passes, and it identifi es 4% of the nonmetallic objects over which it passes. Suppose that 25% of the objects that

Statistics Through Applications 2
Skittles Statistics teacher Jason Molesky contacted the M&M/Mars Company to ask about the color distribution for Skittles. Here is an excerpt of the response he received: Th e original fl avor blend for the SKITTLES BITE SIZE CANDIES is lemon, lime, orange, strawberry and grape. Th ey were chosen as

Statistics Through Applications 2
An online poll In June 2008, Parade magazine posed the following question: Should drivers be banned from using all cell phones? Readers were encouraged to vote online at parade.com. Th e July 13, 2008, issue of Parade reported the results: 2407 (85%) said Yes and 410 (15%) said No. (a) What type of s

Statistics Through Applications 2
Whos left-handed? Students were asked, Are you right-handed, lefthanded or ambidextrous? The responses of the 50 randomly selected Canadian students are shown below (R  right-handed; L  left-handed; A  ambidextrous). R R R R R R R R R R R L R R R R R R R R R R R R R R R A R R R R A R R L R R R R L

Statistics Through Applications 2
Radio station call signs, II Refer to Exercise 8.39. By 1922, there were more applications for radio station licenses than the number of three-letter call signs available. A radio station in New Orleans applied for and was granted the call sign WAAB. (a) How many four-letter call signs start with the

Statistics Through Applications 2
Do you jog? An opinion poll asks an SRS of 1500 adults, Do you happen to jog? Suppose (as is approximately correct) that the population proportion who jog is p 5 0.15. In a large number of samples, the proportion p^ who answer Yes will be approximately Normally distributed with mean 0.15 and standard

Statistics Through Applications 2
Instant opinion A recent online poll posed the question: Should female athletes be paid the same as men for the work they do? In all, 13,147 (44%) said Yes, another 15,182 (50%) said No, and the remaining 1448 said Dont know. (a) What is the sample size for this poll? (b) Th ats a much larger sample

Statistics Through Applications 2
Feeling sleepy? Students in a college statistics class responded to a survey designed by their teacher. One of the survey questions was How much sleep did you get last night? Here are the data (in hours): 9 6 8 6 8 8 6 6.5 6 7 9 4 3 4 5 6 11 6 3 6 6 10 7 8 4.5 9 7 7 (a) Make a dotplot to display the

Statistics Through Applications 2
Plagiarizing An online poll posed the following question: It is now possible for school students to log on to Internet sites and download homework. Everything from book reports to doctoral dissertations can be downloaded free or for a fee. Do you believe giving a student who is caught plagiarizing an

Statistics Through Applications 2
Four-sided dice A tetrahedron (see image) is a pyramid with four faces, each a triangle with all sides equal in length. Label the four faces of a tetrahedral die with 1, 2, 3, and 4 spots. (a) Give a probability model for rolling two such diceone blue and one yellow and recording the number of spots

Statistics Through Applications 2
Sampling variability In thinking about Gallups sample of size 1523, we asked, Could it happen that one random sample finds that 57% of adults recently bought a lottery ticket and a second random sample finds that only 37% had done so? Look at Figure 5.6 (page 224), which shows the results of 1000 sam

Statistics Through Applications 2
Comparing performance: percentiles Peter is a star runner on the track team, and Molly is one of the best sprinters on the swim team. Both athletes qualify for the league championship meet based on their performance during the regular season. (a) In the track playoff s, Peter records a time that woul

Statistics Through Applications 2
IQ test scores, II What percent of IQ scores for all rural Midwest seventh-graders are greater than 100? Explain. How does this compare with the percent in our sample?

Statistics Through Applications 2
Radio station call signs, I In 1912, the U.S. government began issuing licenses to radio stations. Each station was given a unique three-letter call sign. By international agreement, the U.S. eventually received rights to all call signs beginning with the letters W, N, and K. Radio stations in the we

Statistics Through Applications 2
Losing weight A Gallup Poll in November 2008 found that 59% of the people in its sample said Yes when asked, Would you like to lose weight? Gallup announced: For results based on the total sample of national adults, one can say with 95% confi dence that the margin of (sampling) error is 3 percentage

Statistics Through Applications 2
Working backward, II (a) Th e 63rd percentile of the standard Normal distribution. (b) 75% of all observations are greater than z.

Statistics Through Applications 2
Body temperature We have all heard that 98.6 degrees Fahrenheit (or 37 degrees Celsius) is normal body temperature. In fact, there is evidence that most people have a slightly lower body temperature. You plan to measure the body temperature of a random sample of people very accurately. You hope to sh

Statistics Through Applications 2
Making the grade Here are a few lines from a statistics teachers grade book: Name S Homeroom Gr Calculator # Test 1 Hsu, Danny M Blair Sr. B319 81 Iris, Francine F Kingsley Sr. B298 92 Ruiz, Ricardo M Alfonso Jr. B304 87 (a) What individuals does this data set describe? (b) For each individual, what