CSAC2320 Statistical Methods in Business & Accounting - Fall 2020 Section 2 F2F Turned Online Home / My courses / Accounting / Fall 2020 / Accounting FT Post-Graduate Fall 2020 / Section 2 / CSAC2320-025-FT-F20-F2FOnline / Topic 1 / Learning Activity #1 Search forums Learning Activity #1 UNDERSTANDING AND INTERPRETING STATISTICS Part 1 - Who is the Better Shooter in Basketball? At practice last week, Laura scored 2 out of 10 attempts on a basketball hoop. Sarah scored 3 out of 10 attempts. Let’s assume that all shots are taken from the same spot on the basketball court (the three-point line) with no defender. Sarah must be a better shooter. This week, Laura made 53 out of 100 attempts to score a basketball hoop. Sarah scored 6 out of 10 attempts. Sarah is still better. However, let’s add up the scores for BOTH weeks: Laura scored 55 out of 110 shots, that is 50% Sarah scored 9 out of 20 shots, that is only 45% That means Laura is better? Sarah was better last week and this week, but Laura is better over both weeks? ____________________ Part 2 - Examining Correlations In your discussion group, examine some of the correlations on this website (link will open in new window): https://www.tylervigen.com/spurious-correlations Question 2: In your group, discuss what is meant by spurious correlation and the classic phrase “correlation does not imply causation.” Use examples from this website to illustrate your points. ____________________ Part 3 - Issues with Sampling The US presidential election of 1936 pitted Alfred Landon, the Republican governor of Kansas, against the incumbent President, Franklin D. Roosevelt. The year 1936 marked the end of the Great Depression, and economic issues such as unemployment and government spending were the dominant themes of the campaign. Literary Digest was one of the most respected magazines of the time and had a history of accurately predicting the winners of presidential elections that dated back to 1916. For the 1936 election, the Literary Digest prediction was that Landon would get 57% of the vote against Roosevelt's 43% (these are the statistics that the poll measured). The actual results of the election were 62% for Roosevelt against 38% for Landon (these were the parameters the poll was trying to measure). The sampling error in the Literary Digest poll was a whopping 19%, the largest ever in a major public opinion poll. The irony of the situation was that the Literary Digest poll was also one of the largest and most expensive polls ever conducted, with a sample size of around 2.4 million people! At the same time the Literary Digest was making its fateful mistake, George Gallup was able to predict a victory for Roosevelt using a much smaller sample of about 50,000 people. The Literary Digest's method for choosing its sample was as follows: Based on every telephone directory in the United States, lists of magazine subscribers, rosters of clubs and associations, and other sources, a mailing list of about 10 million names was created. Every name on this lest was mailed a mock ballot and asked to return the marked ballot to the magazine. In 1936, telephones were much more of a luxury than they are today. Furthermore, at a time when there were still 9 million people unemployed, the names of a significant segment of the population would not show up on lists of club memberships and magazine subscribers. At least with regard to economic status, the Literary Digest mailing list was far from being a representative cross-section of the population. This is always a critical problem because voters are generally known to vote their pocketbooks, and it was magnified in the 1936 election when economic issues were preeminent in the minds of the voters. Another problem with the Literary Digest poll was that out of the 10 million people whose names were on the original mailing list, only about 2.4 million responded to the survey. Thus, the size of the sample was about one-fourth of what was originally intended. People who respond to surveys are different from people who don't, not only in the obvious way (their attitude toward surveys) but also in more subtle and significant ways. After reading the preceding activity, discuss ONE of the following questions (each individual chooses one) in the Moodle discussion board: Part 1: In your group, explain and interpret this apparent paradox with basketball shooters in Part 1. Part 2: In your group, discuss what is meant by spurious correlation and the classic phrase “correlation does not imply causation”. Use examples from the website in Part 2 to illustrate your points. Part 3: In your group 2, explain some of the potential sampling and non-sampling errors present in the 1936 Literary Digest survey from Part 3. Explain how a smaller sample got a better result, and some of the trade-offs required in creating surveys (e.g., time, cost, representation). Posting a quality post (a few paragraphs minimum) ONCE, including responses to students, is the expectation for a good grade. Post in the Learning Activity #1 discussion forum. The due date for posting to this forum is Monday, 18 January 2021, 11:59 PM. You are not able to create a discussion because you are not a member of any group. Separate groups: All participants (There are no discussion topics yet in this forum) INTELLECTUAL PROPERTY NOTICE Course materials presented on this website are designed for use as part of programs at the York University School of Continuing Studies and are the intellectual property of the York University School of Continuing Studies unless otherwise stated. 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