An article in Medicine and Science in Sports and Exercise "Electrostimulation Training Effects on the Physical Performance of Ice Hockey Players," (2005, Vol. 37, pp. 455-460) considered the use of electromyostimulation (EMS) as a method to train healthy skeletal muscle. EMS sessions consisted of 30 contractions (four-second duration, 85 Hz) and were carried out three times per week for three weeks on 17 ice hockey players. The ten-meter skating performance test showed a standard deviation of 0.09 seconds. Construct a 95% confidence interval of the standard deviation of the skating performance test. Assume population is approximately normally distributed. Round your answers to 3 decimal places.

An article in Medicine and Science in Sports and Exercise "Electrostimulation Training Effects on the Physical Performance of Ice Hockey Players," (2005, Vol. 37, pp. 455-460) considered the use of electromyostimulation (EMS) as a method to train healthy skeletal muscle. EMS sessions consisted of 30 contractions (four-second duration, 85 Hz) and were carried out three times per week for three weeks on 17 ice hockey players. The ten-meter skating performance test showed a standard deviation of 0.09 seconds. Construct a 95% confidence interval of the standard deviation of the skating performance test. Assume population is approximately normally distributed. Round your answers to 3 decimal places.

Holt Mcdougal Larson Pre-algebra: Student Edition 2012

1st Edition

ISBN:9780547587776

Author:HOLT MCDOUGAL

Publisher:HOLT MCDOUGAL

Chapter11: Data Analysis And Probability

Section: Chapter Questions

Problem 8CR

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Is injecting medical cement effective in reducing pain for people who have suffered fractured vertebrae? A paper describes an experiment to compare patients who underwent vertebroplasty (the injection of cement) to patients in a placebo group who underwent a fake procedure. Because the placebo procedure was similar to the vertebroplasty procedure except for the actual injection of cement, patients participating in the experiment were not aware of which treatment they received. All patients were asked to rate their pain at three different times—3 days, 14 days, and 1 month after the procedure. Summary statistics are given in the accompanying table. Pain Intensity VertebroplastyGroup Placebo Group n = 73 n = 76 mean sd mean sd 3 days 4.2 2.8 3.9 2.9 14 days 4.3 2.9 4.5 2.8 1 month 3.9 2.9 4.6 3.0 (a) Construct a 95% confidence interval for the difference in mean pain intensity between the two treatments at 14 days after treatment. (Use ?Vertebroplasty −…
In a study conducted in the Science Department of Faculty of Science, Technology and Human Development in a University; the researcher examined the influence of the drug succinylcholine on the circulation levels of androgens in the blood. Blood samples from wild, free-ranging deer were obtained via the jugular vein immediately after an intramuscular injection of succinylcholine using darts and a capture gun. Deer were bled again approximately 30 minutes after the injection and then released. The level of androgens at time of capture and 30 minutes later, measured in nanograms per milliliter (ng/ml), for 15 deers as in Table Q1. Assuming that the populations of androgen at time of injection and 30 minutes later are normally distributed:i) Find the average and standard deviation of this studyii)Determine the critical region of this problem.iii) Test at the 0.05 level of significance whether the androgen concentrations are altered after 30 minutes of restraint.
An article in Knee Surgery, Sports Traumatology, Arthroscopy, "Arthroscopic meniscal repair with an absorbable screw: results and surgical technique," (2005, Vol. 13, pp. 273-279) cites a success rate of 1% for meniscal tears with a rim width of less than 3 mm, and a 1% success rate for tears from 3-6 mm. If you are unlucky enough to suffer a meniscal tear of less than 3 mm on your left knee, and one of width 3-6 mm on your right knee, what is the probability that you have exactly one successful surgery? assume surgieries are independent.
An article in Knee Surgery, Sports Traumatology, Arthroscopy (2005, Vol. 13, pp. 273-279) considered arthroscopic meniscal repair with an absorbable screw. Results showed that for tears greater than 25 millimeters, 14 of 18 (78%) repairs were successful, but for shorter tears, 22 of 30 (73%) repairs were successful. A doctor would like to know if there is evidence that the success rate is greater for longer tears. The P-value for the test H0: p1 = p2 versus H1: p1 > p2 is closest to:
An issue of Science News (Vol. 163, No. 22, pp. 341-342) reported that the Women’s Health initiative cast doubts on the benefit of hormone -replacement therapy. Researchers randomly divided 4532 healthy women over the age of 65 years into two groups. One group, consisting of 2229 women, received hormone-replacement therapy, the other group, consisting of 2303 women received placebo. Over 5 years, 40 of the women receiving the hormone -replacement therapy were diagnosed with dementia, compared with 21 of those getting placebo. b. Determine and interpret a 90% confidence interval for the difference in dementia risk rates for healthy women over 65 years old who take hormone -replacement therapy and those who do not.
Research done at the Harvard School of Public Health showed that regular soda drinkers may have a tendency toward the weak and brittle bones associated with osteoporosis. They surveyed 2,622 women who were active athletes in college and classified them as to whether they regularly drank soft drinks or rarely drank soft drinks. The proportion of women in each group who suffered from bone fractures was determined. The findings: those who regularly drank soft drinks were twice as likely to suffer from bone fractures as those who rarely drank soft drinks. Source: Health and Fitness News Service, August 21, 1996. a. Was this an observational study or an experiment? Explain.b. What is the population under study?c. What was the explanatory variable?d. What was the response variable?e. What are some possible confounding variables in this study?
Research done at the Harvard School of Public Health showed that regular soda drinkers may have a tendency toward the weak and brittle bones associated with osteoporosis. They surveyed 2,622 women who were active athletes in college and classified them as to whether they regularly drank soft drinks or rarely drank soft drinks. The proportion of women ineach group who suffered from bone fractures was determined. The findings: those who regularly drank soft drinks were twice as likely to suffer from bone fractures as those who rarely drank soft drinks. Source: Health and Fitness News Service, August 21, 1996. What was the response variable? What are some possible confounding variables in this study?
In a study of hypnotic suggestion, 16 male volunteers were randomly allocated to a treatment groupand a control group. Each subject participated in a two-phase experimental session. In the first phase, respiration was measured while the subject was awake and at rest. In the second phase, the subject was told to imagine that he was performing muscular work, and respiration was measured again. For subjects in the treatment group, hypnosis was induced between the first and second phases; thus, the suggestion to imagine muscular work was “hypnotic suggestion” for treatment subjects and “waking suggestion” for control subjects. The table below shows the measurements of total ventilation (liters of air per minute per square meter of body area) for all 16 subjects. (a) For those being hypnotized (treatment group), test the hypotheses H0: μrest = μwork versus Ha:μrest 6= μwork, where μrest and μwork are respectively the mean total ventilation when they are atrest and when they are performing…
A sample of 26 offshore oil workers took part in a simulated escape exercise, resulting in the accompanying data on time (sec) to complete the escape (“Oxygen Consumption and Ventilation During Escape from an Offshore Platform,” Ergonomics, 1997: 281-292): 389 356 359 363 375 424 325 394 402 373 373 370 364 366 364 325 339 393 392 369 374 359 356 403 334 397 a. Construct a stem-and-leaf display of the data. How does it suggest that the sample mean and median will compare?b. Calculate the values of the sample mean and median. [Hint: Σxi = 9638.]c. By how much could the largest time, currently 424, be increased without affecting the value of the sample median? By how much could this value be decreased without affecting the value of the sample median?d. What are the values of x and x when the observations are reexpressed in minutes?
Hormone Therapy and Dementia. An issue of Science News (Vol. 163, No. 22, pp. 341–342) reported that the Women’s Health Initiative cast doubts on the benefit of hormone-replacement therapy. Researchers randomly divided 4532 healthy women over the age of 65 years into two groups. One group, consisting of 2229 women, received hormone-replacement therapy; the other group, consisting of 2303 women, received placebo. Over 5 years, 40 of the women receiving the hormone-replacement therapy were diagnosed with dementia, compared with 21 of those getting placebo. a. At the 5% significance level, do the data provide sufficient evidence to conclude that healthy women over 65 years old who take hormone-replacement therapy are at greater risk for dementia than those who do not? b. Determine and interpret a 90% confidence interval for the difference in dementia risk rates for healthy women over 65 years old who take hormone-replacement therapy and those who do not.
Stressed-Out Bus Drivers. Previous studies have shown that urban bus drivers have an extremely stressful job, and a large proportion of drivers retire prematurely with disabilities due to occupational stress. In the paper, “Hassles on the Job: A Study of a Job Intervention With Urban Bus Drivers” (Journal of Organizational Behavior, Vol. 20, pp. 199–208), G. Evans et al. examined the effects of an intervention program to improve the conditions of urban bus drivers.Amongother variables, the researchers monitored diastolic blood pressure of bus drivers in downtown Stockholm, Sweden. The data, in millimeters of mercury (mm Hg), on the WeissStats site are based on the blood pressures obtained prior to intervention for the 41 bus drivers in the study. Use the technology of your choice to do the following. a. Obtain a normal probability plot, boxplot, histogram, and stemand-leaf diagram of the data. b. Based on your results from part (a), can you reasonably apply the one-mean t-test to the…
The article “Differences in Susceptibilities of Different Cell Lines to Bilirubin Damage” (K. Ngai, C. Yeung, and C. Leung, Journal of Paediatric Child Health, 2000:36–45) reports an investigation into the toxicity of bilirubin on several cell lines. Ten sets of human liver cells and 10 sets of mouse fibroblast cells were placed into solutions of bilirubin in albumin with a 1.4 bilirubin/albumin molar ratio for 24 hours. In the 10 sets of human liver cells, the average percentage of cells surviving was 53.9 with a standard deviation of 10.7. In the 10 sets of mouse fibroblast cells, the average percentage of cells surviving was 73.1 with a standard deviation of 9.1. Find a 98% confidence interval for the difference in survival percentages between the two cell lines.