Question

Say that my husband, Steve is starting a new campaign running for the mayor of Urbana. For a pre-election poll in a dose race, we may want a 95% confidence interval with a small margin of error . Estimate how many people you'd need to poll to get a 95% confidence interval with only a margin of error (Assume the so of the population is around 0.4. Round to the nearest whole number) Tries 0/99 b. Estimate how many people you'd need to poll to get a 95% confidence interval with only a 6 margin of error. (Assume the SD of the population is around 0.42. Round to the nearest whole number) Tries 0/99 compared to part b)? c. Suppose you want to reduce the margin of error to 3%, how would we change the sample si Divided by 4 Divided by 2 Multiplied by 4 Multed by 2 Tres

Answer 1

given that confidence interval - 95% for this confidence interyal we -can eant find a value from 2- value table. For 95% confidence interval 2 = 1.96. @ Number of peoplec sampl Size) we need to pall to gest a 95% confidence interval with only a 5% M = (0.05) Dopo gin of error (S.D. (6) = 0.4). De 175)" 1960.412 C 0.05 ) - (15.60) 2 - 245.8624 7 246 people b). Here. - 6% 0,06 6 0.42 then na 11.96X0.42) (1372) 0.06 = 188.2384 a 198 people
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ere E = 360 - 0.03 620.42 ne (20)2 79.96X0.4992 - 127.4 42 - 752.9536 so s 753 beoble mm 1 0 8 X 4 we multiple by 4 in samble size of b to get 3 % margin error. of