Announcements for 84 upcoming engineering conferences were randomly picked from a stack of IEEE Spectrum magazines The mean length of the conferences was 3 94 days with a standard deviation of 1 28 days Assume the underlying population is normal Determine an 95 confidence interval for the average length of ALL engineering conferences What Procedure would you use Select an answer 2 Sample T Interval Question Help Post to foru T Test Submit Question Jump t T Interval