AP Stats

True or False: A confidence interval gives an interval of plausible values for a parameter based on sample data.

• True

• False

True or False: The confidence interval C gives the overall success rate of the method used to calculate the confidence interval. That is, the interval computed from the sample data will capture the true parameter value in C% of all possible samples when the conditions for inference are met.

• True

• False

The ______________________ of an estimate describes how far, at most, we expect the estimate to vary from the true population value. That is, in a C % confidence interval, the distance between the point estimate and the true parameter value will be less than the margin of error in C % of all samples.

• sample size

• margin of error

• confidence level

• confidence interval

To interpret a confidence level C , say...

• “If we were to select a same size from the same population and construct a C % confidence interval using the sample, about C % of the intervals would capture the [parameter in context].

• “If we were to select 10 random samples of the same size from the same population and construct a C % confidence interval using each sample, about C % of the intervals would capture the [parameter in context].

• “If we were to select many random samples of the same size from the same population and construct a C % confidence interval using each sample, about C % of the intervals would capture the [parameter in context].

Is this a probability distribution?

• No, the sum of p(x) does not equal 1.

• Yes, all p(x) are between 0 and 1.

• No, all p(x) are not between 0 and 1.

• Yes, the sum p(x) is 1.

Is this a probability distribution?

• No

• Yes

• A

• B

• C

• D

• E

The value of that statistic from a sample is called a point _______________ .

To interpret a C% confidence interval for an unknown parameter, say...

• “We are C% confident the answer is (parameter in context)."

• "We are C% the true parameter will be ___."

• "We are C% confident that the interval from ____ to _____ captures the (parameter in context)."

Which critical value corresponds to a 95% confidence level?

• 1.64

• 1.96

• 2.33

• 2.58