Question

A nationwide poll asked a random sample of US adults the question, “Are you in favor of making Election Day a federal holiday?” Based on the results of this poll, the 95% confidence interval for the population proportion who favor making Election Day a federal holiday is (0.64, 0.70).

Calculate the point estimate and margin of error for the given confidence interval.



Enter both values to 2 decimal places.

The point estimate =

The margin of error =

Answer 1

Explanation:

Question: A nationwide poll asked a random sample of US adults the question, "Are you in favor of making Election Day a federal holiday?” Based on the results of this poll, the 95% confidence interval for the population proportion who favor making Election Day a federal holiday is (0.64, 0.70).

Based on this poll, a reporter claims that more than three-fourths of U.S. adults favor making Election Day a federal holiday.

Answer : D

Answer 2

Answer: point estimate = 0.67 and Margin of error = 0.03 .

Explanation:

For confidence interval,

Lower limit = point estimate - margin of error

Upper limit = point estimate + margin of error

Given confidence interval: (0.64, 0.70)

i.e. Lower limit = 0.64

Upper limit = 0.70

i.e. point estimate - margin of error= 0.64 (i)

point estimate + margin of error= 0.70 (ii)

Adding (i) and (ii) , we get

2( point estimate) = 1.34

⇒ point estimate = 0.67

Eliminate (i) from (ii) , we get

2( Margin of error ) = 0.06

⇒ Margin of error = 0.03

Hence, point estimate = 0.67 and Margin of error = 0.03 .