AP Stats Confidence Intervals and Estimation

Question 1

What does a 95% confidence interval mean?

Accepted Answer

If we repeated the sampling many times, 95% of the intervals would contain the true parameter

Answer

There is a 95% probability the true value is in this specific interval

Answer

The data is 95% accurate

Answer

95% of the data falls within this range

Question 2

What happens to the confidence interval as sample size increases?

Accepted Answer

It becomes narrower, providing a more precise estimate

Answer

It becomes wider

Answer

It stays the same

Answer

It shifts to the right

Question 3

What is the relationship between confidence level and interval width?

Accepted Answer

Higher confidence levels produce wider intervals

Answer

Higher confidence levels produce narrower intervals

Answer

There is no relationship

Answer

The relationship depends on sample size only

Question 4

What is the margin of error?

Accepted Answer

Half the width of the confidence interval, representing maximum expected sampling error

Answer

The number of errors in the data

Answer

The difference between the sample mean and zero

Answer

The standard deviation of the sample

Question 5

When are confidence intervals more informative than p-values?

Accepted Answer

When you need to know the magnitude and direction of an effect, not just significance

Answer

Never — p-values are always more informative

Answer

Only in medical research

Answer

Only when sample sizes are very small

Question 6

What does it mean if a confidence interval for a difference includes zero?

Accepted Answer

The difference is not statistically significant at that confidence level

Answer

The true difference is exactly zero

Answer

The study had no power

Answer

The interval is incorrectly calculated