Question

Fake Twitter followers: Many celebrities and public figures have Twitter accounts with large numbers of followers. However, some of these followers are fake, resulting from accounts generated by spamming computers. In a sample of 55 twitter audits, the mean percentage of fake followers was 13.1 with a standard deviation of 10.1. Part: 0 / 2 Part 1 of 2 (a) Construct an 80% confidence interval for the mean percentage of fake Twitter followers. Round the answers to at least one decimal place. An 80% confidence interval for the mean percentage of fake Twitter followers is <u< .

Answer 1

Solution:

Calculate a a 1-Confidence% a 1 0.8 a 0.2 Find a spread range a 2(a) a 2(0.2) a 0.1 Find z-score for a value for 0.1 zscoreo.11.282 <Value can be found on Excel using =NORMSINV(0.9) Calculate the Standard Error of the Mean: SEM g vn SEM 10.1 55 SEM= 10.1 7.4161984870957 SEM 1.3619 Calculate high end confidence interval total: High End X zscorea s/vn High End 13.1 1.282 10.1/155 High End 13.11.282* 1.3618837221757 High End 13.11.7459349318293 1.7459349318293 can be derived on Excel below In Microsoft Excel or Google Sheets, you write this function as CONFIDENCE(0.2,10.1,55) High End 14.8 Calculate low end confidence interval total: Low End X - zscorea s/Nn Low End 13.1 1.282 10.1/155 Low End 13.1 1.282 1.3618837221757 Low End 13.1 1.7459349318293 Low End 11.4 Now we have everything, display our 80% confidence interval: 11.4 H14.8