A study was performed assessing the association between lifetime analgesic intake and change in estimated glomerular filtration rate (GFR) as measured from two blood samples obtained in 1989 and 2000 among 1645 participants in the Nurses’ Health Study (Curhan, et al. [45]). GFR is a commonly used index of kidney
Provide a 95% CI for the OR computed in Problem 13.19.
13.19 What is the estimated odds ratio for being a case comparing Group D to Group A?
Want to see the full answer?
Check out a sample textbook solutionChapter 13 Solutions
Fundamentals of Biostatistics
- Is there a relationship between autism and what an infant is fed? To determine if there is, a researcher asked a random sample of mothers what they had fed their infant and they also recorded whether or not the child was autistic. Almost all brands of formula sold in the U.S. are now fortified with DHA (docosahexaenoic acid) and ARA (arachidonic acid). The data are in the table below. Do the data provide enough evidence to show that that what an infant is fed and autism are dependent? Test at the 1% level and round expected values to one decimal place. what an infant is fed yes (Observed) yes (Expected Value) no (Observed) no (Expected Value) Row Total breastmilk 6 422 428 formula with DHA/ARA 7 1156 1163 formula without DHA/ARA 15 525 540 Column Total 28 2103 2131 H: HypothesesHo:Ho:Select an answer whether or not a child has autism infant infants yes and Select an answer what an infant is fed infant infants no are Select an answer independent…arrow_forwardA cohort study is conducted to assess the association between clinical characteristics and the risk of stroke. The study involves n=1,250 participants who are free of stroke at the study start. Each participant is assessed at study start (baseline) and every year thereafter for five years. The following table displays data on hypertensive status measured at baseline and incident stroke over 5 years. Free of Stroke over 5 Years Stroke Baseline: Not Hypertensive 952 46 Baseline: Hypertensive 234 18 Compute the cumulative incidence of stroke in the study.arrow_forwardReduced heart rate variability (HRV) is known to be a predictor of mortality after a heart attack. One measure of HRV is the average normal-to-normal beat interval (in milliseconds) for a 24-hr time period. Twenty-two heart attack patients who were dog owners and 80 heart attack patients who did not own a dog participated in a study of the effect of pet ownership on HRV, resulting in the summary statistics shown in the accompanying table.arrow_forward
- We are testing whether a particular program of low impact exercise can improve the cholesterol level of stroke patients. We enroll a group of stroke patients in our study, and after six weeks we measure their serum cholesterol level in mmol/L, resulting in the following data: 6.1 9.3 6.3 4 9 5.5 6.3 4.2 4.7 7.8 4.3 7.5 9.1 4.2 6.9 8.1 5.6 9.4 8.3 8.8 7.2 5.7 6.5 3.8 3.8 9 9.4 4.5 8 7 4.5 9.4 6.6 4.1 6.6 9.1 3.9 5.3 (a) Construct a 95% confidence interval. _______< u < ______ From an existing study, we know that the average cholesterol level of all stroke patients is 7 mmol/L. We want to know if the level in our patients is significantly different from this. (b) What is our Test statistic? ______ (c) What is the two-tailed p-value of this result? ______arrow_forwardReduced heart rate variability (HRV) is known to be a predictor of mortality after a heart attack. One measure of HRV is the average normal-to-normal beat interval (in milliseconds) for a 24-hr time period. Twenty-two heart attack patients who were dog owners and 80 heart attack patients who did not own a dog participated in a study of the effect of pet ownership on HRV, resulting in the summary statistics shown in the accompanying table. Measure of HRV(Average Normal-to-Normal Beat Interval) Mean StandardDeviation Owns Dog 871 134 Does Not Own Dog 800 138 (b) The paper indicates that the null hypothesis in part (a) was rejected and reported that the P-value was less than 0.05. Carry out a two-sample t test. (Use ? = 0.05. Use ?1 for heart attack patients who are dog owners and ?2 for heart attack patients who do not own a dog.) Find the test statistic and P-value. (Use SALT. Round your test statistic to one decimal place and your P-value to three decimal places.) t=…arrow_forwardReduced heart rate variability (HRV) is known to be a predictor of mortality after a heart attack. One measure of HRV is the average normal-to-normal beat interval (in milliseconds) for a 24-hr time period. Twenty-two heart attack patients who were dog owners and 80 heart attack patients who did not own a dog participated in a study of the effect of pet ownership on HRV, resulting in the summary statistics shown in the accompanying table. The authors of this paper used a two-sample t test to test H0: ?1 − ?2 = 0 versus Ha: ?1 − ?2 ≠ 0. What conditions must be met in order for this to be an appropriate method of analysis? (Select all that apply.) Find the test statistic and P-value.arrow_forward
- Are seatbelts effective at saving lives? We wish to examine whether or not the use of seatbelts reduces fatalities at the a = 0.01 level of significance. Let pN represent the proportion of non-seatbelt wearing passengers who were involved in a crash and died and py represent the proportion of seatbelt wearing passengers who were involved in a crash and died. NOTE: The data used in this study were obtained through observational study...no experiment was conducted! Which would be correct hypotheses for this test? O Ho:PN = pY, H1:PN > pY Ho: PN = pY, H,:PN Py In a random sample of 321 non-seatbelt wearing passengers involved in a car crash, 30 were killed. In a random sample of 492 seatbelt wearing passengers involved in a car crash, 13 were killed. Find the test statistic (2 decimal places): Give the P-value (4 decimal places - if less than 0.001 answer 0): Which is the correct result: Reject the Null Hypothesis O Do not Reject the Null Hypothesis Which would be the appropriate…arrow_forwardIn a study published in Preventive Medicine (1991), researchers Stampfer and Colditz observed that women who underwent hormone replacement therapy (HRT) showed a lower risk of coronary heart disease (CHD). Identify the explanatory and response variables. Explanatory: Response: Identify a confounding variable that provides an alternative explanation for the reduction in CHD risk among women who underwent HRT, compared to those who didn't undergo HRT. O Left handedness Eye color Blood type O Incomearrow_forwardIn a study published in Preventive Medicine (1991), researchers observed that women who underwent hormone replacement therapy (HRT) showed a lower risk of coronary heart disease (CHD). (a) What are the observational units? does HRT lower risk of CHD? risk of CHD women whether underwent CRT (b) Which of the following is the explanatory variable? whether underwent CRT women does HRT lower risk of CHD? risk of CHD (c) Which of the following is the response variable? does HRT lower risk of CHD? risk of CHD women whether underwent CRTarrow_forward
- A deficiency of the trace element selenium in the diet can negatively impact growth, immunity, muscle and neuromuscular function, and fertility. The introduction of selenium supplements to dairy cows is justified when pastures have low selenium levels. Authors of a research paper supplied the following data on milk selenium concentration (mg/L) for a sample of cows given a selenium supplement (the treatment group) and a control sample given no supplement, both initially and after a 9-day period. Initial Measurement Treatment Control 11.4 9.1 9.6 8.7 10.1 9.7 8.5 10.8 10.2 10.9 10.6 10.6 11.9 10.1 9.9 12.3 10.7 8.8 10.2 10.4 10.3 10.9 11.4 10.4 9.3 11.6 10.6 10.9 10.9 8.3 After 9 Days Treatment Control 138.3 9.2 104 8.9 96.4 8.9 89 10.1 88 9.6 103.8 8.6 147.3 10.4 97.1 12.4 172.6 9.2 146.3 9.5 99 8.4 122.3 8.8 103 12.5 117.8 9.1 121.5 93 (a) Use the given data for the treatment group to determine if…arrow_forwardA deficiency of the trace element selenium in the diet can negatively impact growth, immunity, muscle and neuromuscular function, and fertility. The introduction of selenium supplements to dairy cows is justified when pastures have low selenium levels. Authors of a research paper supplied the following data on milk selenium concentration (mg/L) for a sample of cows given a selenium supplement (the treatment group) and a control sample given no supplement, both initially and after a 9-day period. Initial Measurement Treatment Control 11.2 9.1 9.6 8.7 10.1 9.7 8.5 10.8 10.3 10.9 10.6 10.6 11.7 10.1 9.7 12.3 10.8 8.8 10.3 10.4 10.4 10.9 11.2 10.4 9.4 11.6 10.6 10.9 10.7 8.4 After 9 Days Treatment Control 138.3 9.3 104 8.7 96.4 8.7 89 10.1 88 9.6 103.8 8.6 147.3 10.2 97.1 12.2 172.6 9.3 146.3 9.5 99 8.2 122.3 8.9 103 12.5 117.8 9.1 121.5 93 (a) Use the given data for the treatment group to determine if there…arrow_forwardHeight and Breast Cancer. In the article “Height and Weight at Various Ages and Risk of Breast Cancer” (Annals of Epidemiology, Vol. 2, pp. 597–609), L. Brinton and C. Swanson discussed the relationship between height and breast cancer. The study, sponsored by the National Cancer Institute, took 5 years and involved more than 1500 women with breast cancer and 2000 women without breast cancer; it revealed a trend between height and breast cancer: “. . . taller women have a 50 to 80 percent greater risk of getting breast cancer than women who are closer to 5 feet tall.” Christine Swanson, a nutritionist who was involved with the study, added, “. . . height may be associated with the culprit, . . . but no one really knows” the exact relationship between height and the risk of breast cancer. a. Classify this study as either an observational study or a designed experiment. Explain your answer. b. Interpret the statement made by Christine Swanson in light of your answer to part (a).arrow_forward
- Big Ideas Math A Bridge To Success Algebra 1: Stu...AlgebraISBN:9781680331141Author:HOUGHTON MIFFLIN HARCOURTPublisher:Houghton Mifflin HarcourtGlencoe Algebra 1, Student Edition, 9780079039897...AlgebraISBN:9780079039897Author:CarterPublisher:McGraw Hill