Cengage X \"hA9 Ch 8 M121 × GMost Married × eMost Married× Two ProporticxiMMStat

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Cengage X "hA9 Ch 8 M121 × GMost Married × eMost Married× Two ProporticxiMMState-SpeX Homepage-X DM121 3 Test 3 > Atty C | www.webassign.net/web/Student/Assignment-Responses/last?dep-1741 6886 : Apps D Registration Holds control Panel in Wir Bookmarks Physics-BUS 1120 C 9 How Do l Change M -derivative Nelnet Campus Com EZTV TV Torrents 0 No; np>5 and ng 5 O Yes; np5 and n 5 Need Help?Read It 8. +-12 points BBUnderStat9 8.3.013 My Notes Ask Your Teac For this problem, carry at least four digits after the decimal in your calculations. Answers may vary slightly due to rounding How hard is it to reach a businessperson by phone? Let be the proportion of calls to businesspeople for which the caller reaches the person being called on the first try. (a) If you have no preliminary estimate for p, how many business phone calls should you include in a random sample to be 80% sure that the point estimate p will be within a distance of 0.06 from p? (Round your answer up to the nearest whole number.) phone calls (b) A report states that businesspeople can be reached by a single phone call approximately 18% of the time. Using this (national) estimate for p, answer part (a). (Round your answer up to the nearest whole number.) phone calls Need Help?Read It 9. -3 points BBUnderStat9 8.4.014 My Notes Ask Your Teach ENG 7:08 PM INTL 11/13/20172 " Desktop^

Explanation / Answer

solution:-
(a) If p is unknown, then p = q = 0.5
Confidence level = 80% = 0.8
alpha = 1 - 0.8 = 0.2
alpha/2 = 0.2/2 = 0.1
Z(a/2) = 1.28
Error = 0.06

Formula for error on p-hat:
E=Z(a/2)*sqrt(p*q/n)
Solving for n we get:
n = p*q*(Z/E)^2
n = (.5)(.5)(1.28/.06)^2
n = 113.77
n = 114

(b) p = 18% = 0.18
q = 1 - p = 1 - 0.18 = 0.82
n = (.18)(.82)(1.28/.06)^2
n = 67.17
n = 67

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