Margin Error Confidence Interval

A 95% confidence interval for a population mean is calculated as (150, 210). What is the margin of error?

• 30

• 60

• 180

• 360

To achieve a narrower confidence interval for a given confidence level, one should:

• Increase the sample size.

• Decrease the sample size.

• Increase the standard deviation.

• Decrease the confidence level.

If a 90% confidence interval for a population proportion is calculated as (0.2, 0.4), what is the margin of error?

• 0.1

• 0.2

• 0.3

• 0.4

• 1.64

• 1.96

• 2.33

• 2.58

If a 90% confidence interval for a population proportion is (0.4, 0.6), what is the sample proportion?

• 0.1

• 0.3

• 0.5

• 0.7

• Not enough information to determine.

• 1.64

• 1.96

• 2.33

• 2.58

What does a 95% confidence level mean in the context of constructing a confidence interval?

• There is a 95% chance the sample data is correct.

• 95% of the sample data lies within the interval.

• We are 95% confident that the interval (in context) contains the population parameter.

• We are 95% confident that the sample parameter estimates the population statistic.

For a class project, a student in a statistics class surveys the monthly rent for 32 unfurnished one-bedroom apartments in Boston and finds the mean monthly rent to be $1400 with a standard deviation of $220. Find the margin of error for the sample mean. (assuming 95% confidence) Round to the nearest hundredth

• $77.78

• $4.31

• $188.78

• $494.97

For a class project, a student in a statistics class surveys the monthly rent for 32 unfurnished one-bedroom apartments in Boston and finds the mean monthly rent to be $1400 with a standard deviation of $220. Find the 95% confidence interval for the population mean Round to the nearest hundredth

• [1322.22, 1477.78]

• [1395.69, 1404.31]

• [1211.22, 1588.78]

• [905.03, 1894.97]

A random sample of 45 life insurance policy holders showed that the average premiums paid on their life insurance policies was $340 per year with a standard deviation of $62. Construct a 95% confidence interval for the population mean. Round to the nearest hundredth

• [321.52, 358.48]

• [238.63, 441.37]

• [253.64, 426.36]

• [328.57, 351.43]