A Gallup poll conducted in November 2010 found that 493 of 1

A Gallup poll conducted in November 2010 found that 493 of 1050 adult Americans belive it is the responsibility of the federal goverment to make sure all Americans have healthcare coverage.

a) Obatin a point estimate for the proportion of adult Americans who belive it is the responsibility of the fedral goverment to make sure all Americans have healthcare coverage.

b) Constuct a 95% confidence interval for proportion of adult Americans who belive it is the responsibility of the federal goverment to make sure all Americans have healthcare coverage. Interpret the result.

Please show how you arrived at your solution.

Solution

a) point estimate of proportion = 493/1050 = 0.4695

b)

standard error of mean = sqrt ( 493/1050 * 557/1050 * 1/1050) * 1.96

= 0.0302

cofidence interval = mean +/- standard error

= (0.4695 - 0.0302 , 0.4695 + 0.0302)

= (0.4393,0.4997)