Samples and Margin of Error

A research team surveys 1001 adults, asking them how many hours they work per week. What is the margin of error for this survey?

• 3%

• 32%

• 63%

• 9%

A recent survey found that out of 400 random American adults, 89% pay their bills on time. The margin of error in this survey was 2%. What is the interval of values in which the truth is likely found?

• 89% - 91%

• 87% - 89%

• 87% - 91%

• 388 - 402

A research team surveys 200 high schoolers at glenoak. They find that 57% of them drive to school every day. What is the margin of error?

• 95%

• 14%

• 7%

• 3%

This target depicts what?

• Low bias, low variability

• High bias, low variability

• Low bias, high variability

• High bias, high variability

If the mean of a sample is 203 and the margin of error is 4.6, what would be a reasonable mean for the population?

• 99.2

• 198.3

• 207.2

• 207.7

How could Javier decrease the margin of error?

• Increase the sample size

• Decrease the sample size

What can you do to reduce the margin of error? 

• increase sample size

• decrease sample size

Determine whether the action would increase or decrease the margin of error:

Increase the sample size

• Margin of error increases

• Margin of error decreases

Why is a sample of 1000 people better than a sample of 100 people?

• It reduces the margin of error.

• It decreases bias.

• Having more people is always better.

• More people means that our results are more accurate.

Poll on women’s issues interviewed 1025 women randomly selected from the United States. One question was “Many women have better jobs and more opportunities than they did 20 years ago. Do you think women had to give up too much in the process, or not?” Forty-eight percent of women in the sample said “Yes.” Why can't we just say that 48% of women felt they gave up too much?

• Not all samples would result in 48%

• The margin of error might change.

• The confidence interval might change

• This was a biased survey.