Question

A survey related to professor effectiveness was administered to studentswho chose the professor as the chair of their doctoral committee. The resultsof the survey showed 100% effectiveness. Another survey was administeredto all students taking courses under the professor. The results of this surveyshowed 70% effectiveness. This is a classic example of an error in whichphase of inferential statistics?

Answer 1

For this case we have different effectiveness using two conditions the first one with to students who chose the professor as the chair of their doctoral committe and the second is associated to all students and we see a different effectiveness

This is a clear example of an error in the A)Data Gathering Phase

And the reason is because they introduce bias in the study just selecting students who select the professor as the chair of their doctoral committee, and it's very evident when they select all the students the real results change