“The mean is estimated to fall between (insert LCL) and (insert UCL). This type of estimation is correct (insert confidence level) percent of the time.

This is an accurate interpretation of a confidence level.

There are many correct ways of interpreting a confidence interval estimate. What you CANNOT do however, is make a statement where you associate the probability with the population parameter being estimated. The probability instead should be associated with the sample mean. For example:

WRONG >> “There is a 95% chance that the (population) mean falls between 22 and 29.”

CORRECT >> “The mean is estimated to fall between 22 and 29. This type of estimation is correct 95% of the time”. … or … “If we repeatedly took samples of size n = whatever, 95% would produce an interval estimate that contains the population mean”.

I believe the cheatsheet you provided us has the wrong interpretation?

The cheat sheet shows the definition:

This is an accurate interpretation of a confidence level.

So there are 2 correct interpretations for the confidence level?

There are many correct ways of interpreting a confidence interval estimate. What you CANNOT do however, is make a statement where you associate the probability with the population parameter being estimated. The probability instead should be associated with the sample mean. For example:

WRONG >> “There is a 95% chance that the (population) mean falls between 22 and 29.”

CORRECT >> “The mean is estimated to fall between 22 and 29. This type of estimation is correct 95% of the time”. … or … “If we repeatedly took samples of size n = whatever, 95% would produce an interval estimate that contains the population mean”.

Hi Jason, could you possibly provide a file with the solutions for the longer problems?

The exam section has what you’re looking for with many of the longer question and even the multiple choice that you’ll find there.