In Example, we estimated a model relating number of campus crimes to student enrollment for a sample of colleges. The sample we used was not a random sample of colleges in the United States, because many schools in 1992 did not report campus crimes. Do you think that college failure to report crimes can be viewed as exogenous sample selection? Explain.

In 2000, campbell soup company launched an ad campaign that showed prepubescent boys offering soup to prepubescent girls. the girls declined because they were concerned about their calorie intake. the boys explained that “lots of campbell’s soups are low in calories,” which made them ok for the girls to eat. the ads were pulled after parents expressed concern. why were parents worried? i