Students Struggled With…
When asked why an interval gave results consistent with a two-sided test many students said that it was consistent because the statistic was in the interval so the alternative hypothesis must be true.
Using the statistic when they should have used the null value for the mean and Large Counts.
This is a HUGE misconception! Make sure to thoroughly explain that an interval ALWAYS captures the statistic, that’s how it was created! The statistic will always be exactly in the middle of the confidence interval.
Students need to understand that the null hypothesis is the assumption so the null value should be used for all conditions and calculations. The statistic is only used to find the z – score.