Question

Gallup poll consisted of 1012 randomly selected adults who were asked whether or not cloning of humans should be allowed. 901 of the adults surveyed said that cloning should not be allowed. Construct a 98% confidence interval to estimate the true percentage of all adults who hold this belief. 1. State the Parameter 2. Find the point estimate 3. Check assumptions 4.Find the critical value 5. Find the margin of error 6. Find the confidence interval limits

Answer 1

1. State the Parameter

Proportion of adults in agaisnt cloning of humans should be allowed

2. Find the point estimate

3. Check assumptions

np = 1012*0.89 = 900.68 > 10

n(1-p) = 1012*(1-0.89) = 111.32 > 10

hence, the assumptions are satisfied

4.Find the critical value

At alpha = 0.02 ( 98% confidence interval )

z_c = 2.326

5. Find the margin of error, E

E = 0.023

6. Find the confidence interval limits

CI = ( p^ - E, p^ + E )

CI = ( 0.89 - 0.023 , 0.89 + 0 .023 )

CI = ( 0.867, 0.913 )