JustAnswer



Chapter – 1 SectionAssignment Folder1-2161-3181-4122-2182-310,182-420Statistical Significance and Practical Significance. Determine whether the results appear to have statistical significance, and also determine whether the results have practical significance.16. IQ Scores Most people have IQ scores between 70 and 130. For $32, you can purchase a computer program from that is claimed to increase your IQ score by 10 to 20 points. The program claims to be “the only proven IQ increasing software in the brain training market,” but the author of your text could find no data supporting that claim, so let’s suppose that these results were obtained: In a study of 12 subjects using the program, the average increase in IQ score is 3 IQ points. There is a 25% chance of getting such results if the program has no effect.Answer: No statistical significance because the chance of getting the results if the program has no effect is so high (25%, it should be at least below 10% if there is to be statistical significance).No practical significance because the difference of IQ scores between, say, 110 and 113 is not great enough to make any difference to anyone.Determine whether the given values are from a discrete or continuous data set. 18. Crash Test Results Data Set 13 in Appendix B includes crash test results from 21 different cars.Answer: Discrete dataIdentify which of these types of sampling is used: random, systematic, convenience, stratified, or cluster.12. Ecology When collecting data From different sample locations in a lake, a researcher uses the “line transect method” by stretching a rope across the lake and collecting samples at every interval of 5 meters.Answer:Cumulative Frequency Distributions. Construct the cumulative frequency distribution that corresponds to the frequency distribution in the exercise indicated.18. Exercise 6Constructing Histograms. Construct the histograms and answer the given questions.10. Analysis of Last Digits Use the frequency distribution from Exercise 20 in Section 2-2 to construct a histogram. What can you conclude from the distribution of the digits? Specifically, do the weights appear to be reported or actually measured?18. Flight Taxi-Out Times Use the relative frequency distribution from Exercise 28 in Section 2-2 to construct a histogram. If the quality of air traffic procedures were improved so that the taxi-out times vary much less, would the histogram be affected?Frequency Polygon. Construct the frequency polygon.20. Earthquake Depths Use the frequency distribution from Exercise 24 in Section 2-2 to construct a frequency polygon. Applying a strict interpretation of the requirements f or a normal distribution, do the depths appear to be normally distributed? Why or why not?Chapter – 2 SectionAssignment Folder3 - 2243 - 3243 - 4104 - 2364 - 338Find the mean and median for each of the two samples; then compare the two sets of results.24. Customer Waiting Times Waiting times (in minutes) of customers at the Jefferson Valley Bank (where all customers enter a single waiting line) and the Bank o Providence (where customers wait in individual lines at three different teller windows) are listed below. Determine whether there is a difference between the two data sets that is not apparent from a comparison of the measures of center. If so, what is it?Jefferson Valley (single line): 6.5 6.6 6.7 6.8 7.1 7.3 7.4 7.7 7.7 7.7Providence (individual lines): 4.2 5.4 5.8 6.2 6.7 7.7 7.7 8.5 9.3 10.0Answer: Jefferson Valley: Mean=xn=71.510=7.15Median=7.1+7.32=7.2S=range4=max-min4=7.7-6.54=0.3 Providence: Mean=xn=71.510=7.15Median=6.7+7.72=7.2S=range4=max-min4=10-4.24=1.45We can compare the data by using s. For the first data s is small. But for the second data s is large. Therefore there is more variation in the second dataset.Find the coefficient of variation for each of the two samples; then compare the variation. (The same data were used in Section 3-2.)24. Customer Waiting Times Waiting times (in minutes) of customers at the Jefferson Valley Bank (where all customers enter a single waiting line) and the Bank of Providence (where customers wait in individual lines at three different teller windows) are listed below.Jefferson Valley (single line): 6.5 6.6 6.7 6.8 7.1 7.3 7.4 7.7 7.7 7.7Providence (individual lines): 4.2 5.4 5.8 6.2 6.7 7.7 7.7 8.5 9.3 10.0Answer: For Jefferson Valley: Mean=xn=71.510=7.15Standard deviation s=nx2-(x)2n(n-1) =10513.27-(71.5)210(9) =0.227 =0.476CV=sx=0.4767.15100%=6.66%For Providence:Mean=xn=71.510=7.15Standard deviation s=nx2-(x)2n(n-1) =10541.09-(71.5)210(9) =03.318 =1.822CV=sx=1.8227.15100%=25.48%There is more variation in Providence data set. Usual and Unusual Values. Consider a value to be unusual if its z score is less than -2 or greater than 2.10. Mean or Media? A statistics class with 40 students consists of 30 students with no in-come, 10 students with small incomes from part-time jobs, and a professor with a very large income that is well deserved. Which is better for describing the income of a typical person in this class: mean or median? Explain. Answer: Median, because it is resistant to extreme valuesUsing Probability to Identify Unlikely Events. In Exercises 29–36, consider an event to be “unlikely” if its probability is less than or equal to 0.05. (This is equivalent to the same criterion commonly used in inferential statistics, but the value of 0.05 is not absolutely rigid, and other values such as 0.01 are sometimes used instead.)36. At the End of the Day In a Marist poll, respondents chose the most annoying phrases used in conversation. Nineteen chose “at the end of the day,” 441 chose “whatever,” 235 chose “you know,” 103 chose “it is what it is,” 66 chose “anyway,” and 75 were unsure. Based on these results, what is the probability of selecting someone who considers “at the end of the day” to be the most annoying phrase? At the end of the day, is it unlikely to select someone with that choice?Survey Refusals. 37-38 Refer to the following table summarizing results from a study of people who refused to answer survey questions (based on data from “I Hear You Knocking but You Can’t Come In,” by Fitzgerald and Fuller, Sociological Methods and Research, Vol. 11, No. 1). In each case, assume that one of the subjects is randomly selected.? Age? 18–21 22–29 30–39 40–49 50–59 60 and overResponded73255245136138202Refused11 20 33 16 27 4937. Screening for Marijuana Use Find the probability of a false positive or false negative. What does the result suggest about the test’s accuracy?38. Screening for Marijuana Use Find the probability of a correct result by finding the probability of a true positive or a true negative. How does this result relate to the result from Exercise 37?Chapter – 3 SectionAssignment Folder4 - 4244 - 5304 - 6204 - 6345 - 220In Exercises 24, use these results from the “1-Panel-THC” test for marijuana use, which is provided by the company Drug Test Success: Among 143 subjects with positive test results, there are 24 false positive results; among 157 negative results, there are 3 false negative results. 24. Screening for Marijuana Use If 2 of the subjects are randomly selected without replacement, what is the probability that they both had incorrect test results (either false positive or false negative)? Is such an event unlikely?30. Redundancy in Aircraft Radios he FAA requires that commercial aircraft used for flying in instrument conditions must have two independent radios instead of one. Assume that for a typical flight, the probability of a radio failure is 0.0035. What is the probability that a particular flight will be safe with at least one working radio? Why does the usual rounding rule of three significant digits not work here? Is this probability high enough to ensure flight safety?Exercise 20 and 34 express all probabilities as fractions.20. Illinois Lotterya. In the Illinois Little Lotto game, you win the jackpot by selecting five different whole numbers from 1 through 39 and getting the same five numbers (in any order) that are later drawn. What is the probability of winning a jackpot in this game?b. In the Illinois Pick 3 game, you win a bet by selecting three digits (with repetition allowed) and getting the same three digits in the exact same order as they are later drawn. What is the probability of winning this game?c. The Illinois Pick 3 game returns $500 for a winning $1 ticket. What should be the return if Illinois were to run this game for no profit?34. Mega Millions As of this writing, the Mega Millions lottery is run in 42 states. Winning the jackpot requires that you select the correct five numbers between 1 and 56 and, in a separate drawing, you must also select the correct single number between 1 and 46. Find the probability of winning the jackpot.Car Failures. In Exercises 20, refer to the accompanying table, which describes results of roadworthiness tests of Ford Focus cars that are 3 years old (based on data from the Department of Transportation). The random variable x represents the number of cars that failed among six that were tested for roadworthiness.x P(x)00.37710.39920.17630.04140.0055 0+6 0+20. Range Rule of Thumb for Unusual Events Use the range rule of thumb with the results from Exercise 19 to identify a range of values containing the usual numbers of car failures along six cars tested. Based on the result, is three an unusually high number of failures along six cars tested? Explain. ................
................

In order to avoid copyright disputes, this page is only a partial summary.

Google Online Preview   Download