5. In testing for presence of new bacteria, out the 50 patients examined the number of positive tests was registered and probability of positive results was computed to be 0.455. a. What is the probability of getting negative results out of these 100 patients? Find number of patients with positive test out of 11 randomly selected? b. C. Out of 50 patients what is the probability that a randomly selected patient will either be positive or negative? 6. Consider the following table to answer questions that follows. It is assumed that the ratio of male to female is 1:1. Smoker Non-smoker 80 Total 100 Male Female 90 Total a. Find probability that a randomly selected individual is male smoker? b. Does proportion of male smoker greater than female smoker? C. Suppose that number of male and female smokers increased by 5 persons each. Does probability of female smoker increased relative to that of male? Work out both probabilities. 7. Two researchers A&B test all samples coming to laboratory for signs of new bacteria. Let events: A ={Researcher A makes positive diagnosis) B = (Researcher B makes positive diagnosis) Suppose Researcher A diagnosed 15% of samples as positive and Researcher B diagnosed 20% of samples as positive. Suppose that 15% of the samples on which both researchers disagree on test results were sent for further lab tests. a. Find the proportion of samples that the two researchers agree on the negative test results. b. What percentage of researcher A's negative diagnosis is confirmed by researcher B. 8. Weight of babies born in Addis during the last one decade to mothers from different background was observed and found to have the following parameters: a. = 14 pounds H b. o=2.5 a. Find proportion of mothers with babies' weight more than 20 pounds? b. What proportion of mothers will have babies weight between 13 and 19 pounds? C. What proportion of mothers will have babies weight different from 15 pounds? d. Suppose that 16 mothers were selected from different health service providers and average babies weight estimated to be 12 pounds, what proportion of mothers will have babies with less than this mean (12)? 4_5938318076616379803.docx 2/3