Front

What is a confidence interval?

Back

A confidence interval is a range of values, derived from a data set, that is likely to contain the value of an unknown population parameter. It is used to estimate the uncertainty around a sample statistic.

Front

How do you calculate the margin of error for a confidence interval?

Back

The margin of error is calculated as half the width of the confidence interval. It can be found using the formula: Margin of Error = (Upper Limit - Lower Limit) / 2.

Front

What does a 95% confidence interval indicate?

Back

A 95% confidence interval indicates that if we were to take many samples and build a confidence interval from each sample, approximately 95% of those intervals would contain the true population parameter.

Front

What is the point estimate in a confidence interval?

Back

The point estimate is the midpoint of the confidence interval, calculated as (Lower Limit + Upper Limit) / 2.

Front

If a confidence interval is (10, 20), what is the margin of error?

Back

The margin of error is 5, calculated as (20 - 10) / 2.

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What is the relationship between confidence level and the width of the confidence interval?

Back

As the confidence level increases, the width of the confidence interval also increases, meaning you become more confident that the interval contains the true parameter, but it becomes less precise.

Front

What is the formula for calculating a confidence interval for a population mean?

Back

The formula is: Confidence Interval = Sample Mean ± (Critical Value * Standard Error).

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What does it mean if a margin of error is expressed as a percentage?

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A margin of error expressed as a percentage indicates the range of uncertainty around a sample proportion, showing how much the sample proportion could vary from the true population proportion.

Front

What is the significance of the critical value in confidence intervals?

Back

The critical value is a factor used to compute the margin of error, based on the desired confidence level and the distribution of the sample data.

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How does sample size affect the margin of error?

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As the sample size increases, the margin of error decreases, leading to a more precise estimate of the population parameter.