Margin of Error for Proportions

A preliminary study suggests that 17% of people agree on an issue. How large must your sample size be so you could be within ± 5% with 95% confidence?

• 217

• 30

• 2

• 152

A preliminary study suggests that 87% of people agree on an issue. How large must your sample size be so you could be within ± 3% of p calculate at 90% confidence?

• 7

• 466

• 5

• 338

What is the margin of error of this sample?

• 0.28

• 0.14

• 0.342

• 0.684

If 827 represents "no" voters out of 2584, construct a 95% confidence interval for the "no" group.

• [.300,.340]

• [.298,.342]

• [.302,.338]

• [.288,.352]

Which confidence would result in a larger margin of error (assuming nothing else changed), 91% or 97%?

• 97%

• 91%

• They have the same margin of error.

Increasing the sample size __________ the margin of error.

• increases

• decreases

• does not affect

The amount added and subtracted to the statistic.

• Margin of Error

• Point Estimator

• Statistic

• Population

Decreasing the confidence level from 98% to 95% makes the margin of error

• smaller.

• larger.

• does not affect the interval.

What is the margin of error if the standard error of the proportion is 0.05 and the critical value for a 95% confidence level is 1.96?

• 0.098

• 0.1

• 0.09

• 0.2

Given a sample proportion of 0.3, a sample size of 150, and a 99% confidence level, what is the approximate margin of error?

• 0.13

• 0.08

• 0.12

• 0.09