TC Flashcard on Confidence Interval

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 associated with a confidence level that quantifies the level of confidence that the parameter lies within the interval.

Front

How do you calculate degrees of freedom in a sample?

Back

Degrees of freedom (df) is calculated as the sample size (n) minus 1, so df = n - 1.

Front

What does a margin of error (MOE) indicate in polling?

Back

The margin of error indicates the range within which the true population parameter is expected to fall, given a certain confidence level.

Front

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

Back

As the confidence level increases, the width of the confidence interval also increases, meaning you are more certain that the interval contains the true parameter.

Front

What does a 95% confidence interval mean?

Back

A 95% confidence interval means 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

Which factor does NOT affect the width of a confidence interval?

Back

The sample mean does not affect the width of a confidence interval.

Front

What happens to the confidence interval when the sample size increases?

Back

As the sample size increases, the width of the confidence interval decreases, leading to a more precise estimate of the population parameter.

Front

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

Back

Front

What does it mean if a confidence interval is wider?

Back

A wider confidence interval indicates less precision in estimating the population parameter, but it also suggests a higher level of confidence that the interval contains the true parameter.

Front

What is the effect of increasing the confidence level from 95% to 99% on the confidence interval?

Back

Increasing the confidence level from 95% to 99% will result in a wider confidence interval.