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Stevewh, Bachelor's Degree

Category: Calculus and Above

Satisfied Customers: 7610

Experience: I teach Calculus and Probability in an University since 1994

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Here are my questions for biostatistics
5. A new non-invasive

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Here are my questions for biostatistics 5. A new non-invasive screening test is proposed that is claimed to be able to identify patients with impaired glucose tolerance based on a battery of questions related to health behaviors. The new test is given to 75 patients. Based on each patient’s responses to the questions they are classified as positive or negative for impaired glucose tolerance. Each patient also submits a blood sample and their glucose tolerance status is determined. The results are tabulated below.

Screening Test Impaired Glucose Tolerance Not Impaired Positive 17 13 Negative 8 37

What is the sensitivity of the screening test? b) What is the false positive fraction of the screening test?

6. BMI in children is approximately normally distributed with a mean of 24.5 and a standard deviation of 6.2. a) A BMI between 25 and 30 is considered overweight. What proportion of children are overweight? b) A BMI of 30 or more is considered obese. What proportion of children are obese? c) In a random sample of 10 children, what is the probability that their mean BMI exceeds 25?

7. A national survey is conducted to assess the association between hypertension and stroke in persons over 55 years of age. Development of stroke was monitored over a 5 year follow-up period. The data are summarized below and the numbers are in millions.

Develop Stroke Did not Develop Stroke Hypertension 12 37 No Hypertension 4 26

Compute the incidence of stroke in persons over 55 years of age b) Compute the relative risk of stroke comparing hypertensive to non-hypertensive persons c) Compute the odds ratio of stroke comparing hypertensive to non-hypertensive persons

8. Answer True or False to each of the following a) If there are outliers, then the mean will be greater than the median. b) The 90th percentile of the standard normal distribution is 1.645. c) The mean is the 50th percentile of any normal distribution. d) The mean is a better measure of location when there are no outliers.