Econ 227 Practice Midterm 2024W1 PDF

ECON 227 Jonathan L. Graves Midterm 27 Oct 2024 Name:................................................................................... Student Number :.........................

ECON 227 Jonathan L. Graves Midterm 27 Oct 2024 Name:................................................................................... Student Number :....................................................................... Instructions: Answer all the questions on the exam paper If a question has multiple parts, answer all of them, being sure to label each part. Choose the best option available if unclear. This exam is closed book: you cannot refer to any material when writing this exam. This exam is individual: communication with other students or individuals about or during the exam is forbidden. A non-graphing, non-programmable calculator is permitted. This exam is governed by UBC’s policies on academic integrity and misconduct, as outlined in the course syllabus. Your participation in this exam indicates you agree to abide by them, and these rules, during this exam. You also agree to obey any other instructions given to you by exam invigilators during the course of the exam. Time Permitted: 1:20 minutes Structure: This exam has 8 questions Question: 1 2 3 4 5 6 7 8 Total Points: 2 2 2 2 2 10 15 15 50 Score: Multiple Choice Answers Clearly and completely fill in the bubble with the correct answer for each question. Do not write anything else in the boxed space. If you make an error, erase it completely. Question 1: ⃝ A ⃝ B ⃝ C ⃝ D ⃝ E Question 2: ⃝ A ⃝ B ⃝ C ⃝ D ⃝ E Question 3: ⃝ A ⃝ B ⃝ C ⃝ D ⃝ E Question 4: ⃝ A ⃝ B ⃝ C ⃝ D ⃝ E Question 5: ⃝ A ⃝ B ⃝ C ⃝ D ⃝ E © 2024 Jonathan Graves - Don’t Post Online! ECON 227 Midterm, Page 2 of 7 27 Oct 2024 Multiple Choice Questions 1. (2 points) What type of variables are depicted in Figure 1? Remember: choose the best answer. A. Weight is quantitative, Car type is qualitative. B. Weight is qualitative, Car type is qualitative. C. Weight is quantitative, Car type is a dummy. D. Weight is qualitative, Car type is a dummy. E. Weight is quantitative, Car type is quantitative. Figure 1: A scatterplot 2. (2 points) What is a difference between accuracy and representativeness in evaluating econometric problems using data? A. The presence of intervention. B. Only one refers to the presence few or no errors. C. One refers to samples, the other to population. D. The use in panel data. E. There is no difference! 3. (2 points) Which of the following is an example of an observation that represents some- one at least 15 years old who lives in Quebec, where Ai is the age in years, and Pi is a coded qualitative variable where: © 2024 Jonathan Graves - Don’t Post Online! ECON 227 Midterm, Page 3 of 7 27 Oct 2024 Quebec = 15 Atlantic Canada = 10 Ontario = 14 Northern Canada = 13 Western Canada = 11 Other = 999 A. Pi = Quebec, Ai = 15 B. Pi = 15, Ai = 15 C. Pi = 15, Ai ≤ 15 D. Pi = 15, Ai ≥ 15 E. Pi = 0, Ai = 15 4. (2 points) Consider the chart shown in Figure 2 below. Call the 1979 values (A) and the 2018 values (B). Which of the following statements is correct? A. Both A and B are PDFs. B. A is a PDF, B is a CDF. C. A is a CDF, B is a PDF. D. Both A and B are CDFs. E. None of these answers. 5. (2 points) Which of the following is a correct interpretation of the expression: FY (2.7) = 0.15 where Yi is student i’s GPA? A. 2.7 students have a GPA less than or equal to 0.15 in the population. B. 15% of students have a GPA greater than or equal to 2.7 in the population. C. 15% of students have a GPA less than or equal to 2.7 in the population. D. The probability of having a GPA of 2.7 is 15%. E. None of the above. © 2024 Jonathan Graves - Don’t Post Online! ECON 227 Midterm, Page 4 of 7 27 Oct 2024 Figure 2: A chart Analytical Questions 6. (10 points) Pick two of the following statements, and briefly answer them. Each is worth 5 points. Clearly indicate which ones are you are answering: (a) Suppose you have a set of qualitative variables that each takes on k > 2 levels. How many dummies will you have to use to represent n of these variables? What if you considered the combination of the qualities? (b) Suppose you have a qualitative variable Xi which represents whether personi speaks English for a sample of size n = 100. It is coded as follows: ( 1 if person i speaks English Xi = 2 if person i does not speak English What is X̄i if 75 people speak English? Does this value have an interpretation? (c) Why would you prefer to have quantitative data on a variable rather than qualitative data? Give an example, and at least two reason why. © 2024 Jonathan Graves - Don’t Post Online! ECON 227 Midterm, Page 5 of 7 27 Oct 2024 7. Consider the dialogue, in Figure 3 below, between three students, Salviati, Sagredo, and Simplicio. (a) (5 points) Summarize, briefly, the positions of Salviati and Simplicio. What kinds of statistics are they arguing for? (b) (5 points) In the dialogue, Salviati offers a counterexample to Salviati. What might it have looked like? Sketch it, roughly. (c) (5 points) Based on the ideas developed in class, what do you think of the argu- ments of the debators? Who is more correct, and why? Total for Question 7: 15 8. Consider the visualization in Figure 4. (a) (5 points) Identify the aesthetics used in this visualization and which ones (a) map to variables in the data, and how, or (b) are not mapped to variables. You don’t need to mention aesthetics that only take on one value. (b) (8 points) Assess this visualization based on the principles of effective visualization, explained in class. You should have at least five points of assessment; these might be good, or might be bad. Make sure you identify what message it’s trying to communicate! (c) (2 points) Propose 1 specific improvement you would make to this visualization, and roughly sketch it. Justify your proposal, briefly. Total for Question 8: 15 © 2024 Jonathan Graves - Don’t Post Online! ECON 227 Midterm, Page 6 of 7 27 Oct 2024 Simplicio: I am most concerned about the increasing use of visual methods for under- standing economic data, in contrast to the classical approaches of calculating numerical values. After all, are not some of our greatest achievements to quantify economic objects and make them subject to measurement? Sagredo: I agree. Economics has become so influential because of its role as a quan- titative empirical science. Numbers are essential to the use of statistical tools, and thereby economic modeling! Salviati: I am not so sure. After all, are there not many objects of economic inter- est which are not suitable for simple numerical calculation? After all, if a numerical representation does not show a relationship, could it still exist? Or vice versa? Simplicio: Absurd! Consider the mean, or average, of a dataset. If I find a dataset’s mean is 28, I can be certain that a typical observation will have a value near 28. Only calculation can provide this kind of certainty. Salviati: Now, I quite disagree! Consider the following distribution. (Sketches a figure). Would you not agree this serves as a counterexample? Sagredo: It does seem to me that it is quite the counterexample. What say you, Simplicio? Simplicio: While the mean of your absurd figure is surely a monster, and pathological, it is a counterexample to my naive statement earlier. But such a manipulation would be detected by another form of quantitative calculation. We just need to find such a calculation; say, variance. Salviati: I am quite certain I can find another counterexample to your revised argu- ment. Give me a moment; this becomes more difficult. Simplicio: Ha! See: no matter which pathological monsters you summon to prove your point, I shall always be able to find a new quantitative method which will vanquish them. Sagredo: But is not the value of quantitative calculations their simplicity? If to slay monsters we must make a monster out of our quantitative methods through infinite calculations, have we not lost in any case? Simplicio:... Figure 3: A dialogue concerning two chief approaches © 2024 Jonathan Graves - Don’t Post Online! ECON 227 Midterm, Page 7 of 7 27 Oct 2024 Figure 4: A visualization © 2024 Jonathan Graves - Don’t Post Online! End of Exam