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Concept explainers
Schizophrenia and Dopamine. Previous research has suggested that changes in the activity of dopamine, a neurotransmitter in the brain, may be a causative factor for schizophrenia. In the paper “Schizophrenia: Dopamine β-Hydroxylase Activity and Treatment Response” (Science, Vol. 216, pp. 1423–1425), D. Sternberg et al. published the results of their study in which they examined 25 schizophrenic patients who had been classified as either psychotic or not psychotic by hospital staff. The activity of dopamine was measured in each patient by using the enzyme dopamine β-hydroxylase to assess differences in dopamine activity between the two groups. The following are the data, in nanomoles per milliliter-hour per milligram (nmol/mL-hr/mg).
At the 1% significance level, do the data suggest that dopamine activity is higher, on average, in psychotic patients? (Note: = 0.02426, s1 = 0.00514, = 0.01643, and s2 = 0.00470.)
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Chapter 10 Solutions
INTRO.STATISTICS,TECH.UPDT.-W/MYSTATLAB
- The Lion’sMane. In a study by P. M.West titled “The Lion’s Mane” (American Scientist, Vol. 93, No. 3, pp. 226–236), the effects of the mane of a male lion as a signal of quality to mates and rivals was explored. Four life-sized dummies of male lions provided a tool for testing female response to the unfamiliar lions whose manes varied by length (long or short) and color (blonde or dark). The female lions were observed to see whether they approached each of the four life-sized dummies. a. experimental units. b. response variable. c. factor(s). d. levels of each factor. e. treatments.arrow_forwardA study examined the impact of THC, the active ingredient in marijuana, on various physiological and psychological variables. The study recruited a sample of 18 young adults who were habitual marijuana smokers. Participants came to the lab 3 times, each time completing the entire series of tests and questionnaire, but each time smoking a different marijuana cigarette: one with 3.9% THC, one with 1.8% THC, and one with no THC, a placebo. The order of the conditions was randomized and participants were not told how much THC was in the cigarette they smoked until after all the data were collected. This is an example of a completely randomized experiment. O a case-control observational study. an anecdotal evidence. O a matched pairs or repeated measures experiment. Incorrectarrow_forwardA clinical trial of gamma globulin in the treatment of children with Kawasaki syndrome randomized approximately half of the patients to receive gamma globulin. The standard treatment is an aspirin regimen; however, about one quarter of these patients developed coronary abnormalities even, under the standard treatment. The outcome of interest was the development of coronary abnormalities (CA) over a 7-week follow-up period. The following 2 x 2 table summarizes the results. a) Calculate the odds of developing coronary abnormalities for those who took gamma globulin. Calculate the odds of developing coronary abnormalities for those who took aspirin. (b) Calculate the sample OR for developing coronary abnormalities comparing those on gamma globulin compared to those on aspirin. (c) Investigators constructed the following logistic model: where Logit(i) = log [i / (1 - i) ] = = – 1.0076 – 1.4030 GG Does it make sense to interpret the intercept in this model? If…arrow_forward
- Captivity can influence immunological responses in some mammals. Seeber et al. (2020) investigated various aspects of immunological responses in captive and free-ranging zebras. One aspect of the study involved samples of 12 free-ranging zebras from Namibia, 9 from Tanzania, and 38 captive zebras from various zoos in Europe. (All of these were non-lactating females.) One of the measured variables from blood samples was lysozyme concentration (μg/L). (Lysozyme is a biomarker of the immune response.) The researchers were interested in investigating possible differences in lysozyme concentration between zebras in the various locations. As part of the analysis, they carried out a one-way ANOVA on the lysozyme concentrations for the zebras from the 3 locations, and found the following output. Df Sum Sq Mean Sq F value Pr(>F) Location 2 50.65 25.33 42.24 6.54e-12Residuals 56 33.57 0.60 Suppose the assumptions of one-way ANOVA…arrow_forwardSuppose a study investigated the effects of vitamin A, vitamin C, and omega-3 fatty acids supplements on improving eye health and vision. 300 adults volunteered to take part in the study. In the study, participants were randomly assigned to one of 3 different levels of Vitamin A (Level A, Level B, or Level C) and randomly assigned to one of 2 different levels of Vitamin C (Level 1 or Level 2) and randomly assigned to one of 2 different levels of omega-3 fatty acid (Level I or Level II). a. Identify the subjects of the study. b. Identify the factor(s) for the study and the number of treatment level(s) for each factor. c. How many different treatment groups are there in this study?arrow_forwardConsider the results of a six-year observational study that documented health changes related to homeopathic care (Spence and Thompson 2005). Homeopathic treatment was defined as "stimulating the body's autoregulatory mechanisms using microdoses of toxins." Every one of the 6544 patients in the study was assigned to a hospital outpatient unit for homeopathic treatment. Of these, 4627 patients (70.7%) reported positive health changes following treatment. Suggest a major improvement to the design of this study. (hint: choose one of the six strategies of experimental design) 2. In 1976, Ewan Cameron and Linus Pauling (the only person to have won two unshared Nobel Prizes!) published a paper showing that vitamin C was an effect treatment for some kinds of cancer. They measured the life spans of a sample of 100 patients who were given extra doses of vitamin C. As a control, they pulled the records of several hundred patients from the same clinic who had died from the same types of…arrow_forward
- Pulmonary Hypertension. In the paper “Persistent Pulmonary Hypertension of the Neonate and Asymmetric Growth Restriction” (Obstetrics&Gynecology, Vol. 91, No. 3, pp. 336–341), M. Williams et al. reported on a study of characteristics of neonates. Infants treated for pulmonary hypertension, called the PH group, were compared with those not so treated, called the control group. One of the characteristics measured was head circumference. The mean head circumference of the 10 infants in the PH group was 34.2 centimeters (cm). a. Assuming that head circumferences for infants treated for pulmonary hypertension are normally distributed with standard deviation 2.1 cm, determine a 90% confidence interval for the mean head circumference of all such infants. b. Obtain the margin of error, E, for the confidence interval you found in part (a). c. Explain the meaning of E in this context in terms of the accuracy of the estimate. d. Determine the sample size required to have a margin of error of…arrow_forwardBrunoni et al. (2006) investigated whether the combination of low-level electrical brain stimulation, transcranial direct current stimulation (tDCS), and sertraline, a commonly used SSRI antidepressant, would be effective in decreasing depressive symptoms in a group of clinically depressed individuals. The researchers randomly assigned participants to one of two medication conditions (placebo or sertraline) and to one of two brain electrical stimulation conditions (sham tDCS or active tDCS). How should the ANOVA used to analyze the data be labeled? a. 2 × 2 between-groups ANOVA b. 4 × 2 between-groups ANOVA c. 4 × 2 within-groups ANOVA d. 2 × 2 within-groups ANOVA Clear my choicearrow_forwardPeople who eat lots of fruits and vegetables have lower rates of colon cancer than those who eat little of these foods. Fruits and vegetables are rich in "antioxidants" such as vitamins A, C, and E. Will taking antioxidants help prevent colon cancer? A clinical trial studied this question with 864 people who were at risk for colon cancer. The subjects were divided into four groups: daily beta-carotene, daily vitamins C and E, all three vitamins every day, and daily placebo. After four years, the researchers were surprised to find no significant difference in colon cancer among the groups. What are the explanatory and response variables in this experiment? Explanatory variable Response variable Answer Bank development of colon cancer vitamin regimen the sample size quantity of fruits and vegetables consumedarrow_forward
- 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.arrow_forwardStressed-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…arrow_forwardQ. No. 3: Recently airlines have cut services, such as meals and snacks during flights, and started charging extra for some services, such as accommodating overweight luggage, last-minute flight changes, and pets traveling in the cabin. However, they are still concerned about service. Recently, a group of four carriers hired Brunner Marketing Research Inc. to survey passengers regarding their level of satisfaction with a recent flight. The survey included questions on ticketing, boarding, in-flight service, baggage handling, pilot communication, and so forth. Twenty-five questions offered a range of possible answers: excellent, good, fair, or poor. A response of excellent was given a score of 4, good a 3, fair a 2, and poor a 1. These responses were then totaled, so the total score was an indication of the satisfaction with the flight. The greater the score, the higher the level of satisfaction with the service. The highest possible score was 100. Brunner randomly selected and surveyed…arrow_forward
- Calculus For The Life SciencesCalculusISBN:9780321964038Author:GREENWELL, Raymond N., RITCHEY, Nathan P., Lial, Margaret L.Publisher:Pearson Addison Wesley,
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