Anorexia Nervosa (AN) is a psychiatric condition leading to substantial weight loss among women who are fearful of becoming fat. The article “Adipose Tissue Distribution After Weight Restoration and Weight Maintenance in Women with Anorexia Nervosa” (Amer. J. of Clinical Nutr., 2009: 1132–1137) used whole-body magnetic resonance imagery to determine various tissue characteristics for both an AN sample of individuals who had undergone acute weight restoration and maintained their weight for a year and a comparable (at the outset of the study) control sample. Here is summary data on intermuscular adipose tissue (IAT; kg)
Condition | Sample Mean | Sample SD | |
AN | 16 | .52 | .26 |
Control | 8 | .35 | .15 |
Assume that both samples were selected from
a. Calculate an estimate for true average IAT under the described AN protocol, and do so in a way that conveys information about the reliability and precision of the estimation.
b. Calculate an estimate for the difference between true average AN IAT and true average control IAT, and do so in a way that conveys information about the reliability and precision of the estimation. What does your estimate suggest about true average AN IAT relative to true average control IAT?
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Chapter 9 Solutions
Student Solutions Manual for Devore's Probability and Statistics for Engineering and the Sciences, 9th
- Contamination of various food products is an ongoingproblem all over the world. The article “Prevalence andQuantitative Detection of Salmonella in Retail RawChicken in Shaanxi, China” (J. of Food Production,2013) reported the following data on the occurrence ofsalmonella in chicken of three different types: (1) supermarketchilled, (2) supermarket frozen, and (3) wetmarket fresh slaughtered.Sample Size# SalmonellaPositive Samples1. 60 27Type 2. 60 323. 120 45Does it appear that the incidence rate of salmonellaoccurrence depends on the type of chicken? State andtest the appropriate hypotheses using a significance levelof .05.arrow_forwardIs Seat Belt Use Independent of Cigarette Smoking?A study of seat belt users and nonusers yielded the randomly selected sample data summarized in the given table (based on data from “What Kinds of People Do Not Use Seat Belts?” by Helsing and Comstock,American Journal of Public Health,Vol. 67, No. 11). Test the claim that the amount of smoking is independent of seat belt use. A plausible theory is that people who smoke more 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?arrow_forwardDexamethasone and IQ. In the paper “Outcomes at School Age After Postnatal Dexamethasone Therapy for Lung Disease of Prematurity” (New England Journal of Medicine, Vol. 350, No. 13, pp. 1304–1313), T. Yeh et al. studied the outcomes at school age in children who had participated in a double-blind, placebo-controlled trial of early postnatal dexamethasone therapy for the prevention of chronic lung disease of prematurity. One result reported in the study was that, at school age, the control group of 74 children had an average IQ score of 84.4, whereas the dexamethasone group of 72 children had an average IQ score of 78. a. experimental units. b. response variable. c. factor(s). d. levels of each factor. e. treatments.arrow_forward
- Dexamethasone and IQ. In the paper “Outcomes at School Age After Postnatal Dexamethasone Therapy for Lung Disease of Prematurity” (New England Journal of Medicine, Vol. 350, No. 13, pp. 1304–1313), T. Yeh et al. studied the outcomes at school age in children who had participated in a double-blind, placebo-controlled trial of early postnatal dexamethasone therapy for the prevention of chronic lung disease of prematurity. All of the infants in the study had had severe respiratory distress syndrome requiring mechanical ventilation shortly after birth. On the WeissStats site, we provide the school-age IQs of the 74 children in the control group, based on the study results. 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 one-standard-deviation χ2-procedures to the data? Explain your reasoning. c. Overall, IQs of school-age…arrow_forwardProductivity is the key driver of wages and one of the most importantdeterminants of living standards. The British Chambers of Commercecommissioned research into understanding whether labour productivity in theautomotive manufacturing sector in England and Ireland were the same ordifferent. The researchers collected data on a random sample of 8 firms inEngland and 4 in Ireland and recorded productivity in units of value added (£)per hour. It is assumed that firm-level productivity has a normal distribution.The following data were collected:Ireland 47 56 43 68England 39 50 39 45 50 43 35 43(i) Set up appropriate null and alternative hypotheses and conduct a test ofthe hypotheses of equal mean productivity in Ireland and England at 5 percent significance level under the assumption of unknown but equalpopulation variances. Provide as much detail as possible on yourprocedures. Clearly show all your steps in testing and state your decision.Discuss the economic implications of your findings.…arrow_forwardA Canadian study measuring depression level in teens (as reported in the Journal of Adolescence, vol. 25, 2002) randomly sampled 112 male teens and 101 female teens, and scored them on a common depression scale (higher score representing more depression). The researchers suspected that the mean depression score for male teens is higher than for female teens, and wanted to check whether data would support this hypothesis. If μ1 and μ2 represent the mean depression score for male teens and female teens respectively, which of the following is an appropriate pair of hypotheses in this case? Check all that apply.arrow_forward
- Angioplasty is a medical procedure in which an obstructed blood vessel is widened. In some cases, a wire mesh tube, called a stent, is placed in the vessel to help it remain open. The article “Long-term Outcomes of Patients Receiving Drug-eluting Stents” (A. Philpott, D. Southern, et al., Canadian Medical Association Journal, 2009:167–174) presents the results of a study comparing the effectiveness of a bare metal stent with one that that has been coated with a drug designed to prevent reblocking of the vessel. A total of 5320 patients received bare metal stents, and of these, 841 needed treatment for reblocking within a year. A total of 1120 received drug coated stents, and 134 of them required treatment within a year. a) Find a 98% confidence interval for the differences between the proportions for drug coated stents and bare metal stents. b) Suppose that additional patients are to be treated in order to increase the precision of the confidence interval. Three sampling plans are…arrow_forwardAortic stenosis refers to a narrowing of the aortic valvein the heart. The article “Correlation Analysis ofStenotic Aortic Valve Flow Patterns Using PhaseContrast MRI” (Annals of Biomed. Engr., 2005:878–887) gave the following data on aortic root diameter(cm) and gender for a sample of patients having variousdegrees of aortic stenosis:M: 3.7 3.4 3.7 4.0 3.9 3.8 3.4 3.6 3.1 4.0 3.4 3.8 3.5F: 3.8 2.6 3.2 3.0 4.3 3.5 3.1 3.1 3.2 3.0a. Compare and contrast the diameter observations forthe two genders.b. Calculate a 10% trimmed mean for each of the twosamples, and compare to other measures of center(for the male sample, the interpolation method mentionedin Section 1.3 must be used).arrow_forwardThe article “Arsenic and Mercury in Lake Whitefish and Burbot Near the Abandoned Giant Mine on Great Slave Lake” (P. Cott, B. Zajdlik, et al., Journal of Great Lakes Research, 2016:223–232) presents measurements of arsenic concentrations in fish found in Northern Canada. a) In a sample of 8 whitefish caught in Yellowknife Bay, the mean arsenic concentration in the liver was 0.32 mg/kg, with a standard deviation of 0.05 mg/kg. Find a 95% confidence interval for the concentration in whitefish found in Yellowknife Bay. b) In a sample of 8 whitefish caught in Baker Pond, the mean arsenic concentration in the liver was 0.55 mg/kg, with a standard deviation of 0.36 mg/kg. Should the Student’s t distribution be used to find a 95% confidence interval for the concentration in whitefish found in Baker Pond? If so, find the confidence interval. If not, explain why not.arrow_forward
- Passive exposure to environmental tobacco smoke has been associated with growth suppression and an increased frequency of respiratory tract infections in normal children. Is this association more pronounced in children with cystic fibrosis? To answer this question, 43 children (18 girls and 25 boys) attending a 2-week summer camp for cystic fibrosis patients were studied (New England Journal of Medicine, Sept. 20, 1990). Among several variables measured were the child's weight percentile (y) and the number of cigarettes smoked per day in the child's home (x). a. For the 18 girls, the coefficient of correlation between y and x was reported as r = –.50. Interpret - this result. b. Refer to part a. The p-value for testing Ho: p = 0 against H;: p # 0 was reported as p = .03. n Interpret this result. c. For the 25 boys, the coefficient of correlation between y and x was reported asr = -.12. Interpret %3D %3D this result. d. Refer to part c. The p-value for testing Ho: p = 0 against Ha: p #…arrow_forwardThe paper “Playing Active Video Games Increases Energy Expenditure in Children” (Pediatrics [2009]: 534–539) describes an interesting investigation of the possible cardiovascular benefits of active video games. Mean heart rate for healthy boys age 10 to 13 after walking on a treadmill at 2.6 km/hour for 6 minutes is 98 beats per minute (bpm). For each of 14 boys, heart rate was measured after 15 minutes of playing Wii Bowling. The resulting sample mean and standard deviation were 101 bpm and 15 bpm, respectively. For purposes of this exercise, assume that it is reasonable to regard the sample of boys as representative of boys age 10 to 13 and that the distribution of heart rates after 15 minutes of Wii Bowling is approximately normal. Does the sample provide convincing evidence that the mean heart rate after 15 minutes of Wii Bowling is different from the known mean heart rate after 6 minutes walking on the treadmill? Carry out a hypothesis test using a significance level of 0.01.…arrow_forwardRecycling newsprint is important in reducing waste. The article "The Influence of Newspaper Aging on Optical Properties of its De-inked Pulp" (M. Rahmaninia, A. Latibari, et al., Turkish J Eng Env Sci, 2008:35-39) presents the results of an experiment to determine the effects of the age of newsprint on the brightness (in percent) of the recycled paper. Four aging periods were considered, along with five concentrations of sodium hydroxide (NaOH), used to de-ink the paper. The effect of the sodium hydroxide concentration is not of interest. The results are presented in the following table. NaOH Concentration Age (Months) 2% 0% 0.5% 1% 1.5% 54.6 54.3 55.5 56.3 56.6 4 45.6 44.1 43.7 45.6 47.1 46.1 45.9 46.4 45.0 47.9 12 44.0 44.1 45.2 43.7 46.5 a. Identify the blocking factor and the treatment factor. b. Construct an ANOVA table. You may give ranges for the P-values. Can you conclude that brightness differs with age? Explain. C. d. Which pairs of ages, if any, can you conclude to have…arrow_forward
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