Dr. Guess Who wants to know if students at his university believe that social security will support them in their old age. He sends his graduate students to stand in front of the library and the student union to ask questions of those who pass by. At the end of the day they have 100 responses and find that 24% believe that social security will support them. Dr. Who calculates that the 95% confidence interval is 9%. 3. What sampling technique is used in this study? ________________________________________________________________________ ________________________________________________________________________

5. Evaluate the external validity of this study? Why do you think that? ________________________________________________________________________ ________________________________________________________________________ ________________________________________________________________________ ________________________________________________________________________