A doctor diagnoses a patient as hypertensive and prescribes an antihypertensive medication. To assess the clinical status of the patient, the doctor takes n replicate blood-pressure measurements before the patient starts the drug (baseline) and n replicate blood-pressure measurements 4 weeks after starting the drug (follow-up). She uses the average of the n replicates at baseline minus the average of the n replicates at follow-up to assess the clinical status of the patient. She knows, from previous clinical experience with the drug, that the mean diastolic blood pressure (DBP) change over a 4-week period over a large number of patients after starting the drug is 5.0 mm Hg with variance 33/n, where n is the number of replicate measures obtained at both baseline and follow-up.
If we assume the change in mean DBP is
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Fundamentals of Biostatistics
- Brink studied the effect of postural change on cardiovascular reactivity for a sample of healthy white and African American men and women. Change in systolic blood pressure (SBP) from supine to standing position was used as the measure of cardiac reactivity in a sample of 842 adults. Supine measurement of blood pressure was taken after participants had lain on an examination table for 15 minutes. Blood pressure was measured five times every 2 minutes using a preset automated blood pressure monitor, and the five measurements were averaged. Participants then stood up, and an additional five measurements were made over another 10-minute period and then averaged. Below is a table describing the characteristics of Brink’s sample. Characteristics of the Study Sample (N = 842) Sample Characteristic Frequency (N) Percentage or Mean (SD) Range Gender Female Male 408 434 48.5% 51.5% Age (years) 842 55.1 (5.3) 44–67 Race/ethnicity White, not Hispanic…arrow_forwardA diabetic person is interested in determining how the amount of aerobic exercise impacts his blood sugar. When blood sugar reaches 170 mg/dl, he goes out for a run at a pace of 10 minutes per mile. On different days, he runs different distances and measures his blood sugar after completing his run. The preferred blood sugar level is in the range of 80 to120 mg/dl. Levels that are too low or too high are extremely dangerous. The data generated are given in the following table: Distance (miles),x Blood sugar(mg/dl gram),y 2 136 2 146 2.5 131 2.5 125 3 120 3 116 3.5 104 3.5 95 4 85 4 94 4.5 83 4.5 75 Based on the scenario above, analyse the data with appropriate statistical methods and describe your findings in details. Use alpha=0.05 [note: use hypothesis, test statistics confidence interval etc.] ]arrow_forwardA medical student at a community college in city Q wants to study the factors affecting the systolic blood pressure of a person (Y). Generally, the systolic blood pressure depends on the BMI of a person (B) and the age of the person A. She wants to test whether or not the BMI has a significant effect on the systolic blood pressure, keeping the age of the person constant. For her study, she collects a random sample of 150 patients from the city and estimates the following regression function: Y= 15.50 +0.90B + 1.10A. (0.48) (0.35) The test statistic of the study the student wants to conduct (Ho: B, =0 vs. H4: B, #0), keeping other variables constant is. (Round your answer to two decimal places.) At the 5% significance level, the student will v the null hypothesis. Keeping BMI constant, she now wants test whether the age of a person (A) has no significant effect or a positive effect on the person's systolic blood pressure. So, the test statistic associated with the one-sided test the…arrow_forward
- You are investigating the effect of texting on arthritis. You enroll a cohort of 500 adults ages 65 and older and record their frequency of texting. You follow people over 10 years to collect information on arthritis. At baseline, 300 people in your cohort texted frequently. Of these mothers, 52 developed arthritis. Another 47 people developed arthritis among those not exposed. Calculate the relative risk of arthritis among those exposed to frequent texting and those who were not exposed to frequent texting. Round to the tenth decimal place.arrow_forwardA study was conducted to examine the effect of diet cola consumption on calcium levels in women. A sample of 16 healthy women aged 18 to 40 were randomly assigned to drink 24 ounces of either diet cola or water. Their urine was collected for three hours after ingestion of the beverage and calcium excretion (in mg) was measured. The data are stored in ColaCalcium.arrow_forwardThe owener of a winery collects data on competing wineries every year. He would like to predict the gross sales (in number of cases) from the size of the wineries (in acres). What is the explanatory variable in this study?arrow_forward
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- A doctor studies which type of coronavirus vaccine is best effective.he buys 5 types of vaccines and observes one week from 8am t0 11am ,he measures the pulse rate of each person on of the 10 vacciens Identify the study 1 observational study 2 controlled experiment 3 stratified experiment 4 paired data experiemtnarrow_forwardA psychologist decided to study whether rocking babies in a mechanical baby rocker would affect weight gain. To test this, 8 premature babies at a local hospital were selected to participate in the experiment. The babies were rocked for 10 minutes a day for a week and then weighed. Then the same babies were rocked for 30 minutes a day for a week and then weighed. The change in their weight across the week was measured in ounces. The data and analyses of the t-test, are given below. Note that the difference scores are analyzed as 30-Min minus 10-Min. Baby Rocked 30 Min Rocked 10 Min D = 30 – 10 D2 1 27.6 29.7 -2.1 4.41 2 25.4 28.5 -3.1 9.61 3 30.5 39.8 -9.3 86.49 4 33.8 38.8…arrow_forwardA new screening test for Lyme disease is developed for use in the general population. The sensitivity and specificity of the new test are 60% and 70%, respectively. Five hundred people are screened at a clinic during the first year the new test is implemented. Assume the true prevalence of Lyme disease among clinic attendees is 10%. Calculate the predictive value of a positive test.arrow_forward
- Glencoe Algebra 1, Student Edition, 9780079039897...AlgebraISBN:9780079039897Author:CarterPublisher:McGraw Hill