Homework 1: Chapter 1

First Questiona) From a large sample of randomly selected fourth graders, I would randomly

select half of them to attend large classes (30+ students) and the other half to attend small classes (15 and less students). At the end of the year I would assign a standardized test and compare the average for the two groups.

b) If the correlation were negative, that would mean that the larger the classroom, the worse the test-score. This result may very well have been because smaller classrooms are more conducive for learning than larger ones.

c) No, because there are many other variables to consider such as socioeconomic status, school rating, and even the accuracy of standardized testing as a gage for better performance.

Second Questiona) One would have to assume that the firms given were equal in every way (pay,

working conditions, supervisors, lighting…), except for how much they trained their workers.

b) Yes, because the firms will hire workers based on their characteristics before training them in the first place. Some measurable or observable characteristics are job experience, education level, gender, and even race. Some immeasurable characteristics include motivation to actually do well and skillfulness.

c) Other factors include type of machinery, the characteristics of the supervisors, pay, and working environment.

d) Not unless all other factors in the firms are exactly equal or the amount of training each worker receives is randomly assigned.

Third QuestionNo, because it does not make sense to say that one causes the others. Students usually choose a mix of activities to fill their time depending on their needs (studying, sleeping, partying, working, volunteering, interning…). Working and studying are just two variables that the student chooses; one doesn’t cause the other.