If we have calculated a confidence interval and we find that it does NOT include the population mean,
A) we must have done something wrong in collecting data.
B) our interval was too wide.
C) we made a mistake in calculation.
D) this will happen a fixed percentage of the time.

Question

Quizplus · Accepted Answer

Confidence intervals are constructed to contain the population mean a certain percentage of the time, typically 95% or 99%. This means that a certain percentage of the time (5% for a 95% confidence interval), the interval will not contain the population mean purely due to sampling variability. This is an expected part of statistical inference and does not necessarily indicate a mistake in data collection or calculation.

If We Have Calculated a Confidence Interval and We Find