Concept explainers
The paper “Breast MRI as an Adjunct to Mammography for Breast Cancer Screening in High-Risk Patients” (American Journal of Roentgenology [2015]: 889–897) describes a study that investigated the usefulness of MRI (magnetic resonance imaging) to diagnose breast cancer. MRI exams from 650 women were reviewed. Of the 650 women, 13 had breast cancer, and the MRI exam detected breast cancer in 12 of these women. Of the 637 women who did not have breast cancer, the MRI correctly identified that no cancer was present for 547 of them. The accompanying table summarizes this information.
Suppose that an MRI exam is used to decide between the two hypotheses
H0: A woman does not have breast cancer
Ha: A woman has breast cancer
(Although these are not hypotheses about a population characteristic, this exercise illustrates the definitions of Type I and Type II errors.)
- a. One possible error would be deciding that a woman who has breast cancer is cancer-free. Is this a Type I error or a Type II error? Use the information in the table to approximate the
probability of this type of error. - b. There is a second type of error that is possible in this context. Describe this error and use the information in the table to approximate the probability of this type of error.
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Chapter 10 Solutions
Introduction To Statistics And Data Analysis
- A pathological video game user (PVGU) is a video game user that averages 31 or more hours a week of gameplay. According to the article “Pathological Video Game Use among Youths: A Two-Year Longitudinal Study” (Pediatrics, Vol. 127, No. 2, pp. 319–329) by D. Gentile et al., in 2011, about 9% of children in grades 3–8 were PVGUs. Suppose that, today, five youths in grades 3–8 are randomly selected. Let X represent the number of youths who are PVGUs. n = p = 1 – p = Prepare the probability distribution for the random variable X. Complete the following table. Round your answers to 4 decimal places e.g. 0.XXXX or .XXXX. X = x P(X=x) 0 1 2 3 4 5 ∑=1.0000∑=1.0000 Calculate the probability that EXACTLY three youths are PVGUs. Round your answers to 4 decimal places e.g. 0.XXXX or .XXXX. P(X = 3) = Calculate the probability that AT LEAST two youths are PVGUs. Round your answers to 4 decimal places e.g. 0.XXXX or .XXXX. P(X ≥ 2) = Calculate the…arrow_forwardA colonoscopy is a medical procedure that is designed to find and remove precancerous lesions in the colon before they become cancerous. The article “Association of Colonoscopy and Death from Colorectal Cancer” reports that in a sample of 10,292 people diagnosed with colorectal cancer, 7.1% had previously had a colonoscopy. In a sample of 51,460 people without colorectal cancer, 9.8% had previously had a colonoscopy. 25. Can you conclude that the percentage of people who have had colonoscopies is greater in those without colorectal cancer? Use ? = 0.01arrow_forwardA paper describes a study of the use of MRI (Magnetic Resonance Imaging) exams in the diagnosis of breast cancer. The purpose of the study was to determine if MRI exams do a better job than mammograms of determining if women who have recently been diagnosed with cancer in one breast have cancer in the other breast. The study participants were 940 women who had been diagnosed with cancer in one breast and for whom a mammogram did not detect cancer in the other breast.These women had an MRI exam of the other breast, and 111 of those exams indicated possible cancer. After undergoing biopsies, it was determined that 30 of the 111 did in fact have cancer in the other breast, whereas 81 did not. The women were all followed for one year, and four of the women for whom the MRI exam did not indicate cancer in the other breast were subsequently diagnosed with cancer that the MRI did not detect. The accompanying table summarizes this information. CancerPresent Cancer NotPresent Total MRI…arrow_forward
- In their study of the effectiveness of cardiac catheterization, McClellan,McNeil, and Newhouse (1994) used as an instrument the difference indistance to cardiac catheterization and regular hospitals. How could youdetermine whether this instrument is relevant? How could you determinewhether this instrument is exogenous?arrow_forwardResearchers recruited 1000 10- and 20-year-olds to participate in a study about age differences in aggression and the impact of violent video games on aggression. For 1-hour per day, half the participants were randomly assigned to play violent video games, while the other half played a nonviolent video game. A test for aggression was administered at the end of the year, and each participant received a score between 1 and 50 (higher scores indicate greater aggression). The results of the study are shown below: Factor 1 10 years 20 years old old Violent 35 25 Factor games 2 Nonviolent 25 45 games Is there a main effect of age? If so, which age shows more aggression?arrow_forwardOne study of cell phones and the risk of brain cancer looked at a group of 469 people who have brain cancer. The investigators then asked about the use of cell phones. Result: “Our data suggest that the use of hand- held cellular phones is not associated with risk of brain cancer. B . Based on this study, can you determine that cellular use does not CAUSE brain cancer? Why or why not?arrow_forward
- A paper describes a study of the use of MRI (Magnetic Resonance Imaging) exams in the diagnosis of breast cancer. The purpose of the study was to determine if MRI exams do a better job than mammograms of determining if women who have recently been diagnosed with cancer in one breast have cancer in the other breast. The study participants were 950 women who had been diagnosed with cancer in one breast and for whom a mammogram did not detect cancer in the other breast. These women had an MRI exam of the other breast, and 101 of those exams indicated possible cancer. After undergoing biopsies, it was determined that 30 of the 101 did in fact have cancer in the other breast, whereas 71 did not. The women were all followed for one year, and four of the women for whom the MRI exam did not indicate cancer in the other breast were subsequently diagnosed with cancer that the MRI did not detect. The accompanying table summarizes this information. Cancer Cancer Not Present Present Total MRI…arrow_forwardSleep apnea is a disorder in which there are pauses in breathing during sleep. People with this condition must wake up frequently to breathe. The article “Postoperative Complications in Patients With Obstructive Sleep Apnea Syndrome Undergoing Hip or Knee Replacement: A Case-Control Study” (R. Gupta, J. Parvizi, et al., Mayo Clinic Proceedings, 2001:897–905) reported that in a sample of 427 people 65 and over, 104 of them had sleep apnea. a) Find a 95% confidence interval for the proportion of those 65 and over who have sleep apnea. b) Find a 99% confidence interval for the proportion of those 65 and over who have sleep apnea. c) Find the sample size needed for a 95% confidence interval to specify the proportion to within ±0.03. d) Find the sample size needed for a 99% confidence interval to specify the proportion to within ±0.03.arrow_forwardHepatitis B and Pancreatic Cancer. The article “Study Links Hepatitis B and Cancer of Pancreas” by D. Grady, appeared in the September 29, 2008 issue of the NewYork Times. It reported that, for the first time, a study showed that people with pancreatic cancer are more likely than those without the disease to have been infected with the hepatitis B virus. The study by M. Hassan et al., titled “Association Between Hepatitis B Virus and Pancreatic Cancer” (Journal of Clinical Oncology, Vol. 26, No. 28, pp. 4557–4562) compared 476 people who had pancreatic cancer with 879 healthy control subjects. All were tested to see whether they had ever been infected with the viruses that cause hepatitis B or hepatitis C. The results were that no connection was found to hepatitis C, but the cancer patients were twice as likely as the healthy subjects to have had hepatitis B. The researchers noted, however, that “. . . while the study showed an association, it did not prove cause and effect. More work…arrow_forward
- A case−control study was performed among 145 subjects with macular degeneration and 34 controls, all of whom were 70- to 79-year-old women. A genetic risk score was developed to help differentiate the cases from the controls. The risk score was categorized into six groups (1, 2, 3, 4, 5, 6), with 6 being the highest risk and 1 being the lowest risk.The data in Table 10.48 were obtained relating the risk score to case/control status. taBlE 10.48 risk score cases controls 1 3 11 2 7 3 3 6 6 4 10 8 5 11 2 6 108 4 total 145 34 10.139 What test can be performed to study the asso- ciation between case/control status and risk score? Spe- cifically, we are interested in testing whether cases tend to have consistently higher risk scores or consistently lower risk scores than controls.arrow_forwardA recent study investigated the association between sudden cardiac death and smoking history in women from a large health system. The epidemiologist reviewed the electronic health records of women who died from sudden cardiac death (n=80) and women who died of non-cardiac causes (n=80). The investigator then reviewed these records for smoking history (smoking 1+ pack/day and smoking <1 pack/day) and identified the following results. Sudden Cardiac Death 38 42 Smoke 1+ pack/day Smoke <1 pack/day Calculate the most appropriate measure of association for these data (a)-round to the nearest tenth. Other Causes 10 70arrow_forwardGinkgo for Dementia. The herb ginkgo biloba is commonly used as a treatment to prevent dementia. In a study of the effectiveness of this treatment, 1545 elderly subjects were given ginkgo and 1524 elderly subjects were given a placebo. those in the ginkgo group, 246 later developed dementia, and among those in the placebo group, 277 later developed dementia ( based on data from " Ginkgo Biloba for Prevention of Dementia," by DeKosky et al., Journal of the American Medical Association, Vol. 300No. 19). We want to use a 0.01 significance level to test the claim that ginkgo is effective in preventing dementia.arrow_forward
- Calculus For The Life SciencesCalculusISBN:9780321964038Author:GREENWELL, Raymond N., RITCHEY, Nathan P., Lial, Margaret L.Publisher:Pearson Addison Wesley,