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Concept explainers
Does exercise help blood pressure? Several recent studies have suggested that people who suffer from abnormally high blood pressure can benefit from regular exercise. A medical researcher decides to test her belief that walking briskly for at least half an hour a day has the effect of lowering blood pressure. She conducts a small pilot study. If results from it are supportive, she will apply for funding for a larger study. She randomly samples three of her patients who have high blood pressure. She measures their systolic blood pressure initially and then again a month later after they participate in her exercise program. The table shows the results.
- a. Explain why the three before observations and the three after observations are dependent samples.
- b. Find the sample
mean of the before scores, the sample mean of the after scores, and the sample mean of the difference scores d = before – after. How are they related? - c. Find a 95% confidence interval for the difference between the population means of subjects before and after going through such a study. Interpret.
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Chapter 10 Solutions
Statistics: The Art and Science of Learning From Data, Books a la Carte Edition (4th Edition)
- What is an experiment?arrow_forwardA scientist is studying the effect of a new type of exercise program on cardiovascular health. The scientist randomly assigns individuals to either the exercise program or a control group. The scientist wants to determine if the exercise program has a statistically significant effect on cardiovascular health. The scientist monitors cardiovascular health by measuring the blood pressure of each individual.arrow_forwardA diabetic person is interested in determining how the amount of aerobic exercise impacts his blood sugar. When blood sugar reaches 170 mg/dl, he goes out for a run at a pace of 10 minutes per mile. On different days, he runs different distances and measures his blood sugar after completing his run. The preferred blood sugar level is in the range of 80 to120 mg/dl. Levels that are too low or too high are extremely dangerous. The data generated are given in the following table: Distance (miles),x Blood sugar(mg/dl gram),y 2 136 2 146 2.5 131 2.5 125 3 120 3 116 3.5 104 3.5 95 4 85 4 94 4.5 83 4.5 75 Based on the scenario above, analyse the data with appropriate statistical methods and describe your findings in details. Use alpha=0.05 [note: use hypothesis, test statistics confidence interval etc.] ]arrow_forward
- Sleep apnea is a condition in which the sufferers stop breathing momentarily while they are asleep. This condition results in lack of sleep and extreme fatigue during waking hours. A current estimate is that 10 million out of the 312.7 million Americans suffer from sleep apnea, or approximately 3.2%. A safety commission is concerned about the percentage of commercial truck drivers who suffer from sleep apnea. They do not have any reason to believe that it would be higher or lower than the population’s percentage. To test the claim that the percentage of commercial truck drivers who suffer from sleep apnea is not 3.2%, a simple random sample of 409 commercial truck drivers is examined by a medical expert, who concludes that 21 suffer from sleep apnea. Does this evidence support the claim that the percentage of commercial truck drivers who suffer from sleep apnea is not 3.2%? Use a 0.05 level of significance. Step 2 of 3 : Compute the value of the test statistic. Round your…arrow_forwardSleep apnea is a condition in which the sufferers stop breathing momentarily while they are asleep. This condition results in lack of sleep and extreme fatigue during waking hours. A current estimate is that 16.3 million out of the 312.7 million Americans suffer from sleep apnea, or approximately 5.2%. A safety commission is concerned about the percentage of commercial truck drivers who suffer from sleep apnea. They do not have any reason to believe that it would be higher or lower than the population’s percentage. To test the claim that the percentage of commercial truck drivers who suffer from sleep apnea is not 5.2%, a simple random sample of 380380 commercial truck drivers is examined by a medical expert, who concludes that 29 suffer from sleep apnea. Does this evidence support the claim that the percentage of commercial truck drivers who suffer from sleep apnea is not 5.2%? Use a 0.01 level of significance. Step 1 of 3 : State the null and alternative hypotheses for the test.…arrow_forwardSleep apnea is a condition in which the sufferers stop breathing momentarily while they are asleep. This condition results in lack of sleep and extreme fatigue during waking hours. A current estimate is that 9.7 million out of the 312.7million Americans suffer from sleep apnea, or approximately 3.1%A safety commission is concerned about the percentage of commercial truck drivers who suffer from sleep apnea. They do not have any reason to believe that it would be higher or lower than the population’s percentage. To test the claim that the percentage of commercial truck drivers who suffer from sleep apnea is not 3.1%, a simple random sample of 406commercial truck drivers is examined by a medical expert, who concludes that 55 suffer from sleep apnea. Does this evidence support the claim that the percentage of commercial truck drivers who suffer from sleep apnea is not 3.1%?Use a 0.05 level of significance. Step 3 of 3 : Draw a conclusion and interpret the decision.arrow_forward
- You are asked to design a study to investigate the effectiveness of the Atkins diet (IV = diet, DV = weight loss). Describe a study that would utilize a dependent t test as the test statistic.arrow_forwardIn an article about unusual allergies, a doctor explained that allergy to sulfites is usually seen in patients with asthma. The typical reaction is a sudden increase in asthma symptoms after eating a food containing sulfites. Studies are performed to estimate the percentage of the nation's 10 million asthmatics who are allergic to sulfites. In one survey, 33 of 500 randomly selected asthmatics in the country were found to be allergic to sulfites. Find and interpret a 95% confidence interval for the proportion, p, of all asthmatics in the country who are allergic to sulfites. Click here to view page 1 of the table of areas under the standard normal curve. Click here to view page 2 of the table of areas under the standard normal curve. ..... The 95% confidence interval is from to (Round to three decimal places as needed.)arrow_forwardSleep apnea is a condition in which the sufferers stop breathing momentarily while they are asleep. This condition results in lack of sleep and extreme fatigue during waking hours. A current estimate is that 15 million out of the 312.7 million Americans suffer from sleep apnea, or approximately 4.8%. A safety commission is concerned about the percentage of commercial truck drivers who suffer from sleep apnea. They do not have any reason to believe that it would be higher or lower than the population’s percentage. To test the claim that the percentage of commercial truck drivers who suffer from sleep apnea is not 4.8%, a simple random sample of 339 commercial truck drivers is examined by a medical expert, who concludes that 7 suffer from sleep apnea. Does this evidence support the claim that the percentage of commercial truck drivers who suffer from sleep apnea is not 4.8%? Use a 0.05 level of significance. Step 3 of 3 : Draw a conclusion and interpret the decision.…arrow_forward
- Sleep apnea is a condition in which the sufferers stop breathing momentarily while they are asleep. This condition results in lack of sleep and extreme fatigue during waking hours. A current estimate is that 12.8 million out of the 312.7 million Americans suffer from sleep apnea, or approximately 4.1%. A safety commission is concerned about the percentage of commercial truck drivers who suffer from sleep apnea. They do not have any reason to believe that it would be higher or lower than the population’s percentage. To test the claim that the percentage of commercial truck drivers who suffer from sleep apnea is not 4.1%, a simple random sample of 392 commercial truck drivers is examined by a medical expert, who concludes that 2424 suffer from sleep apnea. Does this evidence support the claim that the percentage of commercial truck drivers who suffer from sleep apnea is not 4.1%? Use a 0.02 level of significance. Step 3 of 3 : Draw a conclusion and interpret the decision. 1.…arrow_forwardIn an article about unusual allergies, a doctor explained that allergy to sulfites is usually seen in patients with asthma. The typical reaction is a sudden increase in asthma symptoms after eating a food containing sulfites. Studies are performed to estimate the percentage of the nation's 10 million asthmatics who are allergic to sulfites. In one survey, 22 of 400 randomly selected asthmatics in the country were found to be allergic to sulfites. Find and interpret a 90% confidence interval for the proportion, p, of all asthmatics in the country who are allergic to sulfites. Click here to view page 1 of the table of areas under the standard normal curve. Click here to view page 2 of the table of areas under the standard normal curve. The 90% confidence interval is from to. (Round to three decimal places as needed.) Interpret the confidence interval. Choose the correct answer below. O A. With 90% confidence, the true proportion of all asthmatics in the country who are allergic to…arrow_forwardSleep apnea is a condition in which the sufferers stop breathing momentarily while they are asleep. This condition results in lack of sleep and extreme fatigue during waking hours. A current estimate is that 12.8 million out of the 312.7 million Americans suffer from sleep apnea, or approximately 4.1%. A safety commission is concerned about the percentage of commercial truck drivers who suffer from sleep apnea. They do not have any reason to believe that it would be higher or lower than the population’s percentage. To test the claim that the percentage of commercial truck drivers who suffer from sleep apnea is not 4.1%, a simple random sample of 392 commercial truck drivers is examined by a medical expert, who concludes that 24suffer from sleep apnea. Does this evidence support the claim that the percentage of commercial truck drivers who suffer from sleep apnea is not 4.1%? Use a 0.02 level of significance. Step 2 of 3: Compute the value of the test statistic. Round your…arrow_forward
- Glencoe Algebra 1, Student Edition, 9780079039897...AlgebraISBN:9780079039897Author:CarterPublisher:McGraw HillBig Ideas Math A Bridge To Success Algebra 1: Stu...AlgebraISBN:9781680331141Author:HOUGHTON MIFFLIN HARCOURTPublisher:Houghton Mifflin Harcourt
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