Featured image of article: Statistics Students Learn To Determine Confidence Intervals

Statistics Students Learn To Determine Confidence Intervals

There is an air of friendly competition among the 25 juniors and seniors in Sam Winslow’s Statistics class. Today’s challenge to the students who are working in groups or individually: to determine confidence intervals when certain variables, such as the population mean (μ), are unknown.

A confidence interval displays the probability that a certain parameter will fall between a pair of values around the mean. In other words, it measures the degree of certainty or uncertainty in a sampling method. Confidence intervals are most often constructed using levels of 95% or 99%.

For example, if a survey is conducted on a sample of a population (e.g., sample n=100 out of a city population of N=100,000), the confidence interval tells you both the possible range around the estimate and also how stable the estimate is. A stable estimate is one that would be close to the same value if the survey were repeated.