The article “Brain Shunt Tested to Treat Alzheimer’s” (San Francisco Chronicle, October 23, 2002) summarizes the findings of a study that appeared in the journal Neurology. Doctors at Stanford Medical Center were interested in determining whether a new surgical approach to treating Alzheimer’s disease results in improved memory functioning. The surgical procedure involves implanting a thin tube, called a shunt, which is designed to drain toxins from the fluid-filled space that cushions the brain. Eleven patients had shunts implanted and were followed for a year, receiving quarterly tests of memory
- a. What were the researchers trying to learn? What questions motivated their research?
- b. Do you think that the study was conducted in a reasonable way? What additional information would you want in order to evaluate this study?
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Chapter 1 Solutions
Introduction To Statistics And Data Analysis
- Patients immobilized for a substantial amount of time can develop deep vein thrombosis (DVT), a blood clot in a leg or pelvis vein. DVT can have serious adverse health effects and can be difficult to diagnose. On its website, drug manufacturer Pfizer reports the outcome of a study looking at the effectiveness of the drug Fragmin (dalteparin) in preventing DVT in immobilized patients. Of the 1518 randomly chosen immobilized patients given Fragmin, 42 experienced a complication from DVT. Of the 1473 randomly chosen immobilized patients given a placebo, 73 experienced a complication from DVT. Compute the proportion (risk) of patients experiencing DVT complications for immobilized patients treated with Fragmin. (Enter the proportion with 4 decimal places. DO NOT enter the percent.)arrow_forwardSleep apnea is a sleep disorder characterized by pauses in breathing during sleep. Children with sleep apnea have behavior problems, including hyperactivity, inattention, and aggression, as well as impaired learning and diminished academic performance. The removal of tonsils and adenoids that are enlarged, causing the obstruction of the airways, is one of the most common treatments for pediatric sleep apnea. A clinical psychologist studies the effects of tonsillectomy and adenoidectomy on hyperactive behavior. Her quasi-experiment includes three groups of 11 children. The first group of children does not have sleep apnea, the second group has untreated sleep apnea, and the third group has sleep apnea treated by tonsillectomies and adenoidectomies. Hyperactivity was measured using teacher reports on the Conners Rating Scale. The sample means and sums of squared deviations of the scores for each of the three groups are presented in the table that follows. Group Sample Mean Sum…arrow_forwardAppalachian Bear Rescue (ABR) is a not-for-profit organization located near the Great Smoky Mountains National Park. ABR's programs include the rehabilitation of orphaned and injured black bears, as well as research and education about Appalachian black bears. ABR provides the most natural environment possible for rehabilitating black bears before their release back into the wild. Recently, Katie Settlage performed a study to learn more about the Appalachian black bear population in the Great Smoky Mountains National Park. She and a team of researchers found 68 black bears in the park and took measurements such as paw size, weight, and shoulder height. The stem-and-leaf plots below show the shoulder heights (in centimeters) of the 40 male and 28 female bears from the study. Shoulder Heights (in cm) of Male Bears Shoulder Heights (in cm) of Female Bears 4 9 Key: 4 9 = 49 Key: 5|0 = 50 5 7 8 9 71 1 2 2 2 2 2 3 3 3 4 4 5 5 6 6 788 8 123 4 4 5 6 79 90 0 3 6 79 7 8 1 2 3 3 3 33 4 6 7 555 5…arrow_forward
- Measles is a highly contagious infection of the respiratory system and is caused by a virus. Despite the fact that more than 80% of the world’s population is vaccinated for it, measles remains the fifth leading cause of death worldwide. In general, the term pathogenesis refers to the way a disease originates and develops over time. In the case of measles, the virus enters through the respiratory tract and replicates there before spreading into the bloodstream and then the skin.The measles pathogenesis function used to model the development of the disease is given by the following equation: f (t) = −t (t − 21) (t + 1) Where t is measured in days and f (t) represents the number of infected cells per millilitre [mL] of plasma. What is the peak infection time for the measles virus? Solve the above problem through the following steps: (a)Expand equation f (t) = −t (t − 21) (t + 1) in fully. (b) Calculate the first derivative f′ (t), of the equation found in part (a). (c) Find the…arrow_forwardMeasles is a highly contagious infection of the respiratory system and is caused by a virus. Despite the fact that more than 80% of the world’s population is vaccinated for it, measles remains the fifth leading cause of death worldwide. In general, the term pathogenesis refers to the way a disease originates and develops over time. In the case of measles, the virus enters through the respiratory tract and replicates there before spreading into the bloodstream and then the skin. Figure 1: Shown is a transmission electron micrograph of a measles virus. The measles pathogenesis function used to model the development of the disease is given by the following equation: f (t) = −t (t − 21) (t + 1) Where t is measured in days and f (t) represents the number of infected cells per millilitre [mL] of plasma. What is the peak infection time for the measles virus? Solve the above problem through the following steps: (a) Expand equation 2 fully. (b) Calculate the first derivative f′ (t), of the…arrow_forwardMeasles is a highly contagious infection of the respiratory system and is caused by a virus. Despite the fact that more than 80% of the world’s population is vaccinated for it, measles remains the fifth leading cause of death worldwide. In general, the term pathogenesis refers to the way a disease originates and develops over time. In the case of measles, the virus enters through the respiratory tract and replicates there before spreading into the bloodstream and then the skin.Figure 1: Shown is a transmission electron micrograph of a measles virus.1The measles pathogenesis function used to model the development of the disease is given by the following equation: f (t) = −t(t − 21)(t + 1) (2)where t is measured in days and f (t) represents the number of infected cells per milliliter [mL] of plasma. What is the peak infection time for the measles virus? Solve the above problem through the following steps:(a) Expand equation 2 fully. [1] (b) Calculate the first derivative f′ (t), of the…arrow_forward
- In August and September 2005, Hurricanes Katrina and Rita caused extraordinary flooding in New Orleans, Louisiana. Many homes were severely damaged or destroyed; of those that survived, many required extensive cleaning. It was thought that cleaning flood-damaged homes might present a health hazard due to the large amounts of mold present in many of the homes. The article “Health Effects of Exposure to Water-Damaged New Orleans Homes Six Months After Hurricanes Katrina and Rita” (K. Cummings, J. Cox-Ganser, et al., American Journal of Public Health, 2008:869–875) reports that in a sample of 365 residents of Orleans Parish who had participated in the cleaning of one or more homes, 77 had experienced symptoms of wheezing, and in a sample of 179 residents who had not participated in cleaning, 23 reported wheezing symptoms (numbers read from a graph). Can you conclude that the frequency of wheezing symptoms is greater among those residents who participated in the cleaning of flood-damaged…arrow_forwardA biochemist is testing the effect of a new antibiotic on a particulararrow_forwardDairy cattle are cattle that are bred for their ability to produce large quantities of milk. Lameness is a condition that can be detrimental to cattle since it can be painful and result in deleterious effects on the animal’s welfare. It is a condition in which cows have difficulty moving and especially walking. Investigators are interested in whether milk production in dairy cows is associated with whether or not the cow becomes lame. They think that the age of the cow (young or old) may confound and/or modify the relationship between milk production and lameness and so they collect information on the age of the cows as well. The data that cross classifies lame status and milk production status is stratified by age and provided in the tables below. Use SAS to complete each part. (a) Ignoring age, report the estimate for the OR and its corresponding 95% confidence interval. Interpret both. (b) Ignoring age, is milk production associated with lameness? Justify your response using a…arrow_forward
- A researcher hypothesized that children's cholesterol levels may be affected by educating their parents on proper nutrition and exercise. A random sample of 40 families with a child between the ages of 10 to 15 who had been diagnosed with high cholesterol were recruited to participate in the study. All parents were provided with educational information on nutrition and exercise. After following the prescribed program, the child's total cholesterol was measured. The children's (the sample) mean cholesterol level was 185 with a standard deviation of 19.5. Is there significant evidence of that their cholesterol level after this intervention is lower than the population mean of 191?arrow_forwardBody Fat. J. McWhorter et al. of the College of Health Sciences at the University of Nevada, Las Vegas, studied physical therapy students during their graduate-school years. The researchers were interested in the fact that, although graduate physical-therapy students are taught the principles of fitness, some have difficulty finding the time to implement those principles. In the study, published as “An Evaluation of Physical Fitness Parameters for Graduate Students” (Journal of American College Health, Vol. 51, No. 1, pp. 32–37), a sample of 27 female graduate physical-therapy students had a mean of 22.46 percent body fat. a. Assuming that percent body fat of female graduate physicaltherapy students is normally distributed with standard deviation 4.10 percent body fat, determine a 95% confidence interval for the mean percent body fat of all female graduate physical-therapy students. b. Obtain the margin of error, E, for the confidence interval you found in part (a). c. Explain the…arrow_forwardBeryllium is an extremely lightweight metal that is used in many industries, such as aerospace and electronics. Long-term exposure to beryllium can cause people to become sensitized. Once an individual is sensitized, continued exposure can result in chronic beryllium disease, which involves scarring of the lungs. In a study of the effects of exposure to beryllium, workers were categorized by their duration of exposure (in years) and by their disease status (diseased, sensitized, or normal). The results were as follows: Duration of Exposure <1 1 to <5 ≥5 Diseased 14 13 18 Sensitized 11 20 15 Normal 78 140 209 Test the hypothesis of independence. Use the a=0.10 level of significance and the P-value method with the TI-84 Plus calculator. What do you conclude? State the null and alternate hypotheses.arrow_forward
- Linear Algebra: A Modern IntroductionAlgebraISBN:9781285463247Author:David PoolePublisher:Cengage Learning