Students Struggled With…
Interpreting a confidence level vs. a confidence interval.
Thinking a larger sample size increases the confidence level. When comparing a 95% confidence interval that was created from a sample size of 100 to a 95% confidence interval that was created from a sample of 50, students often think that the interval made from 100 will capture the true parameter more often.
Warn students before the quiz that they will be asked to interpret both an interval and a level. Often, students incorrectly interpret a level as an interval because they are working too quickly and assume they are being asked to interpret a confidence interval without noticing the question is asking for a level.
Have students interpret the confidence level for each interval. They should notice before they interpret the second interval that the interpretation is exactly the same. This helped clear up the misunderstanding for our students.