Question

1. A poll of 2234 U.S. adults found that 31% regularly used Facebook as a news source.

Find the margin of error and confidence interval for the percentage of U.S. adults who regularly use Facebook as a news source, at the 90% level of confidence. Round all answers to 2 decimal places.

Margin of Error (as a percentage):
Confidence Interval: % to %

Find the margin of error and confidence interval for the percentage of U.S. adults who regularly use Facebook as a news source, at the 95% level of confidence. Round all answers to 2 decimal places.

Margin of Error (as a percentage):
Confidence Interval: % to %

Find the margin of error and confidence interval for the percentage of U.S. adults who regularly use Facebook as a news source, at the 99% level of confidence. Round all answers to 2 decimal places.

Margin of Error (as a percentage):
Confidence Interval: % to %

The more error we allow, the less precise our estimate. Therefore, as the confidence level increases, the precision of our estimate

• increases
• decrease
• stays roughly the same

2. Assume that a sample is used to estimate a population proportion p. Find the 95% confidence interval for a sample of size 186 with 56% successes.

1. Enter your answer as an open-interval (i.e., parentheses) using decimals (not percents) accurate to three decimal places.

   Confidence interval =

2. 
   
3. Express the same answer as a tri-linear inequality using decimals (not percents) accurate to three decimal places.

   < p <

4. 
   
5. Express the same answer using the point estimate and margin of error. Give your answers as decimals, to three places.

   p = ±±

3. We wish to estimate what percent of adult residents in a certain county are parents. Out of 600 adult residents sampled, 330 had kids. Based on this, construct a 95% confidence interval for the proportion p of adult residents who are parents in this county.

Express your answer in tri-inequality form. Give your answers as decimals, to three places.

< p < Express the same answer using the point estimate and margin of error. Give your answers as decimals, to three places.

p = ±±

Answer 1