Concept explainers
Use the following information to answer the next seven exercises: A ballet instructor is interested in knowing what percent of each year’s class will continue on to the next, so that she can plan what classes to offer. Over the years, she has established the following
Let X = the number of years a student will study ballet with the teacher.
Let P(x) = the probability that a student will study ballet x years.
You ate playing a game by drawing a card from a standard deck and replacing it. If the card is a face card, you win $30. If it Is not a face card, you pay $2. There are 12 face cards in a deck of 52 cards. Should you play the game?
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Chapter 4 Solutions
Introductory Statistics
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Calculus: Early Transcendentals (2nd Edition)
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- Find the regression equation, letting the first variable be the predictor (x) variable. Using the listed lemon/crash data, where lemon imports are in metric tons and the fatality rates are per 100,000 people, find the best predicted crash fatality rate for a year in which there are 475 metric tons of lemon imports. Is the prediction worthwhile? Use a significance level of 0.05. Lemon Imports 235 264 356 Crash Fatality Rate 16 15.9 15.6 476 518 15.3 D 15.1 Find the equation of the regression line. + (Round the y-intercept to three decimal places as needed. Round the slope to four decimal places as needed.) The best predicted crash fatality rate for a year in which there are 475 metric tons of lemon imports is fatalities per 100,000 population. (Round to one decimal place as needed.) Is the prediction worthwhile? OA. Since there appears to be an outlier, the prediction is not appropriate. OB. Since all of the requirements for finding the equation of the regression line are met, the…arrow_forwardA study of seat belt users and nonusers yielded the randomly selected sample data summarized in the accompanying table. Use a 0.05 significance level to test the claim that the amount of smoking is independent of seat belt use. A plausible theory is that people who smoke are less concerned about their health and safety and are therefore less inclined to wear seat belts. Is this theory supported by the sample data? Click the icon to view the data table. Determine the null and alternative hypotheses. OA. Ho: The amount of smoking is dependent upon seat belt use. H₁: The amount of smoking is not dependent upon seat belt use. OB. Ho: Heavy smokers an H₁: Heavy smokers an OC. Ho: The amount of sm H₁: The amount of sm OD. Ho Heavy smokers an H₁: Heavy smokers ar Determine the test statistic. x²= (Round to three decin More Info Number of Cigarettes Smoked per Day 0 1-14 15-34 35 and over Wear Seat Belts 193 20 42 9 Don't Wear Seat Belts 159 10 41 9 Determine the P-value of the t P-Value =…arrow_forwardAssume that the amounts of weight that male college students gain during their freshman year are normally distributed with a mean of μ = 1.3 kg and a standard deviation of o=5.5 kg. Complete parts (a) through (c) below. a. If 1 male college student is randomly selected, find the probability that he gains between 0 kg and 3 kg during freshman year. The probability is (Round to four decimal places as needed.) b. If 9 male college students are randomly selected, find the probability that their mean weight gain during freshman year is between 0 kg and 3 kg. The probability is (Round to four decimal places as needed.) c. Why can the normal distribution be used in part (b), even though the sample size does not exceed 30? OA. Since the distribution is of sample means, not individuals, the distribution is a normal distribution for any sample size. OB. Since the weight gain exceeds 30, the distribution of sample means is a normal distribution for any sample size. OC. Since the original…arrow_forward
- Find the area of the shaded region. The graph to the right depicts IQ scores of adults, and those scores are normally distributed with a mean of 100 and a standard deviation of 15. Click to view page 1 of the table. Click to view page 2 of the table. The area of the shaded region is ☐ (Round to four decimal places as needed.) 95 125arrow_forwardThe accompanying table lists the ages of acting award winners matched by the years in which the awards were won. Construct a scatterplot, find the value of the linear correlation coefficient r, and of r. Determine whether there is sufficient evidence to support a claim of linear correlation between the two variables. Should we expect that there would be a correlation? Use a significance level of a = 0.05. Click the icon to view the ages of the award winners. Best Actresses and Best Actors Construct a scatterplot. Choose the correct graph below. OA. Best Actor (years) 70- 17 OB. Best Actresses and Best Actors OC. 20- 20 70 Best Actress 27 30 30 62 33 32 46 30 58 23 45 51 Best Actress (years) Best Actor 43 37 37 44 47 47 56 49 40 56 46 34 The linear correlation coefficie (Round to three decimal place Determine the null and alterna Print Done Ho P H₁ P (Type integers or decimals. Do not round.) The test statistic is t= (Round to two decimal places as needed.) The P-value is (Round to…arrow_forwardA data set includes data from student evaluations of courses. The summary statistics are n = 93, x=3.83, s = 0.68. Use a 0.10 significance level to test the claim that the population of student course evaluations has a mean equal to 4.00. Assume that a simple random sample has been selected. Identify the null and alternative hypotheses, test statistic, P-value, and state the final conclusion that addresses the original claim. What are the null and alternative hypotheses? OA. Ho μ*4.00 H₁ =4.00 OC. Ho p=4.00 H₁:p>4.00 Determine the test statistic. (Round to two decimal places as needed.) Determine the P-value. ☐ (Round to three decimal places as needed.) State the final conclusion that addresses the original claim. Ho. There is OB. Ho H=4.00 H₁ #4.00 OD. Ho p=4.00 Η μ < 4.00 evidence to conclude that the mean of the population of student course evaluations is equal to 4.00 correct.arrow_forward
- Listed below are the lead concentrations (in μg/g) measured in different Ayurveda medicines. Ayurveda is a traditional medical system commonly used in India. The lead concentrations listed here are from medicines manufactured in the United States. Assume that a simple random sample has been selected. Use a 0.05 significance level to test the claim that the mean lead concentration for all such medicines is less than 14.0 µg/g. 2.99 6.50 6.03 5.51 20.49 7.48 12.03 20.51 11.50 17.51 Identify the null and alternative hypotheses. Ho H₁₁ (Type integers or decimals. Do not round.) Identify the test statistic. 1 (Round to two decimal places as needed.) Identify the P-value. (Round to three decimal places as needed.) State the conclusion about the null hypothesis, as well as the final conclusion that addresses the original claim. the null hypothesis. There sufficient evidence at the 0.05 significance level to the claim that the mean lead concentration for all Ayurveda medicines manufactured in…arrow_forwardMany people believe that criminals who plead guilty tend to get lighter sentences than those who are convicted in trials. The accompanying table summarizes randomly selected sample data for defendants in burglary cases. All of the subjects had prior prison sentences. Use a 0.05 significance level to test the claim that the sentence (sent to prison or not sent to prison) is independent of the plea. If you were an attorney defending a guilty defendant, would these results suggest that you should encourage a guilty plea? Click the icon to view the table. More Info OA. Ho: The sentence (sent to prison or not sent to prison) is not independent of the plea. H₁: The sentence (sent to prison or not sent to prison) is independent of the plea. OB. Ho Pleading guilty reduces a defendant's chance of going to prison. H₁: Pleading guilty doe OC. Ho: Pleading guilty doe H₁: Pleading guilty red More Info OD. Ho: The sentence (sen H₁: The sentence (sen Determine the test statistic. x²=(Round to three…arrow_forwardClaim: Fewer than 95% of adults have a cell phone. In a reputable poll of 1081 adults, 86% said that they have a cell phone. Find the value of the test statistic The value of the test statistic is (Round to two decimal places as needed.) 13arrow_forward
- Suppose that in a random selection of 100 colored candies, 22% of them are blue. The candy company claims that the percentage of blue candies is equal to 24%. Use a 0.10 significance level to test that claim. O A. Ho p=0.24 H₁ p 0.24 OB. Ho p=0.24 H₁ p>0.24 OC. Ho p=0.24 H₁: p<0.24 OD. Ho p# 0.24 H₁ p=0.24 Identify the test statistic for this hypothesis test. The test statistic for this hypothesis test is (Round to two decimal places as needed.) Identify the P-value for this hypothesis test The P-value for this hypothesis test is ☐ (Round to three decimal places as needed.) Identify the conclusion for this hypothesis test. E OA. Reject Ho. There is not sufficient evidence to warrant rejection of the claim that the percentage of blue candies is equal to 24% OB. Reject Ho. There is sufficient evidence to warrant rejection of the claim that the percentage of blue candies is equal to 24% OC. Fail to reject Ho. There is sufficient evidence to warrant rejection of the claim that the…arrow_forwardRandomly selected birth records were obtained, and categorized as listed in the table to the right. Use a 0.01 significance level to test the reasonable claim that births occur with equal frequency on the different days of the week. How might the apparent lower frequencies on Saturday and Sunday be explained? Day Number of Births Determine the null and alternative hypotheses. Ho H₁ Sun 45 Mon 64 Tues 56 Wed 62 Thurs 59 2 Calculate the test statistic, x² x²=(Round to three decimal places as needed.) Calculate the P-value. P-value = (Round to four decimal places as needed.) What is the conclusion for this hypothesis test? OA. Reject Ho. There is insufficient evidence to warrant rejection of the claim that births occur with equal frequency on the different days of the week. OB. Fail to reject Ho. There is insufficient evidence to warrant rejection of the claim that births occur with equal frequency on the different days of the week. OC. Reject Ho. There is sufficient evidence to warrant…arrow_forwardListed below are annual data for various years. The data are weights (metric tons) of imported lemons and car crash fatality rates per 100,000 population. Construct a scatterplot, find the value of the linear correlation coefficient r, and find the P-value using a = 0.05. Is there sufficient evidence to conclude that there is a linear correlation between lemon imports and crash fatality rates? Do the results suggest that imported lemons cause car fatalities? Lemon Imports Crash Fatality Rate 229 264 359 483 533 15.9 15.6 15.4 15.3 14.8 17- 16- 15- of D р 17- 17- 17- 16 O о o E X D 16- 0 0 G 15 15 ° 16- 0 e O G 15 X 14+ 0 14+ 200 400 600 0 200 400 600 14- 0 200 400 600 The linear correlation coefficient is r= (Round to three decimal places as needed.) The test statistic is t= ☐ (Round to three decimal places as needed.) The P-value is ☐ (Round to three decimal places as needed.) Because the P-value is than the significance level 0.05, there significance level of α = 0.05. 14- 0 200 400…arrow_forward
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