Question

In the spring of 2017, the Consumer Reports National Research Center conducted a survey of 1,007 adults to learn about their major healthcare concerns. The survey results showed that 575 of the respondents lack confidence they will be able to afford health insurance in the future.

(a)

What is the point estimate of the population proportion of adults who lack confidence they will be able to afford health insurance in the future. (Round your answer to two decimal places.)

(b)

At 90% confidence, what is the margin of error? (Round your answer to four decimal places.)

(c)

Develop a 90% confidence interval for the population proportion of adults who lack confidence they will be able to afford health insurance in the future. (Round your answer to four decimal places.)

? to ?

(d)

Develop a 95% confidence interval for this population proportion. (Round your answer to four decimal places.)

? to ?

Answer 1

a)

Sample proportion = 575 / 1007 = 0.571

Point estimate of proportion = 0.571

b)

Margin of error Z/2 * sqrt [ ( 1 - ) / n]

= 1.6449 * sqrt [ 0.571 * ( 1 - 0.571) / 1007 ]

= 0.0257

c)

95% confidence interval for p is

- E < p < + E

0.571 - 0.0257 < p < 0.571 + 0.0257

0.5453 < p < 0.5967

90% CI is ( 0.5453 , 0.5967 )

d)

95% confidence interval for p is

- Z/2 * sqrt [ ( 1 - ) / n] < p < + Z/2 * sqrt [ ( 1 - ) / n]

0.571 - 1.96 * sqrt [ 0.571 * ( 1 - 0.571) / 1007 ] < p < 0.571 + 1.96 * sqrt [ 0.571 * ( 1 - 0.571) / 1007 ]

0.5404 < p < 0.6016

95% CI is ( 0.5404 , 0.6016 )