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eText Book Here! 2017FA MAT × A M3 Assignment Sign In www.webassign.net/web/Stud

ID: 3364449 • Letter: E

Question

eText Book Here! 2017FA MAT × A M3 Assignment Sign In www.webassign.net/web/Student/Assignment-Responses/last?depe 168 133% a. Search uppei I Need Help?Read tMaster I 18. + 2 points BBUnderStat12 7.3023M My Notes Ask Your Teacher For this problem, carry at least four digits after the decimal in your calculations. Answers may vary slightly due to rounding A random sample of medical files is used to estimate the proportion p of all people who have blood type B (a) If you have no preliminary estimate for p, how many medical files should you include in a random sample in order to be 85% sure that the point estimate p will be within a distance of 0.04 from p? (Round your answer up to the nearest whole number.) medical files (b) Answer part (a) if you use the preliminary estimate that about 10 out of 90 people have blood type B medical files Need Help? .Readid Master 840 PM O Type here to search ^ dx E 11/19/2017

Explanation / Answer

a.) Given 85 % CI, z = 1.4395 , error = 0.04 , p = 0.5

n = (z/error)^2*p*(1-p) = (1.4395/0.04)^2*0.5*0.5 = 323.7750 = 324 (rounded)

b.) p = 10/90 = 0.1111

n = (z/error)^2 p (1-p) = (1.4395/0.04)^2*0.1111*0.8889 = 127.8999 = 128 (rounded)