Question

A Gallup poll asked a random sample of 1000 adults nationwide the following question "Are you in favor of the death penalty for a person convicted of murder?" 71% of the people in the sample answered 'Yes' Click here to view the normal table 1. What most closely resembles the relevant box model?

Answer 1

It is given that a Gallop poll asked a random sample of size n= 1000. It is given that 71% of the people in the sample answered "Yes". The relevant model is that it has millions of tickets marked with "O"'s and "1"'s. The exact percentages are unknown but are estimated from the sample. Let the proportion of those who answered "Yes" be p = 0.71. Let the level of significance be a = 0.05. The critical z-value is obtained from the standard normal table and is z. = 1.96. The 95% confidence interval for the percent of all adults nation-wide in favor of the death penalty is given as follows: CI = D= 7//B(1,5 €) Vn = 71% 1.96 x 10.71(0.29) 1000 = 71%+(1.96x0.0143) = 71% 2.80%

Let the level of significance be a =0.01. The critical z-value is obtained from the standard normal table and is z = 2.58. The 99% confidence interval for the percent of all adults nation-wide in favor of the death penalty is given as follows: p(1-2) CI = + 2x = 71%=(2,58%, 1000) = 71%+(2.58 0.0143) = 71%3.69%