Making Fair Comparisons: An Approach to Quantitative Literacy Written by: Mike Caulfield Editors & Contributors: Becca Berkey, Elli Caldwell This work is heavily influenced by the work of Milo Schield, Neil Lutsky, and Nathan Grawe. The questions we ask here are questions they ask, although the presentation and focus of this text is someone different. This [...]
Uncategorized
Mental Experiments and the Mancovery
This is the new story out — it’s a mancovery! From Bloomberg: Men, who lost more than twice as many jobs as women during the worst economic slump since the Great Depression, have landed 88 percent of the non-farm jobs created since the recession ended in June 2009. The share of men saying the economy [...]
Glossary: Median Income (U.S. Census)
From the Census definition: Median income is the amount which divides the income distribution into two equal groups, half having incomes above the median, half having incomes below the median. The medians for households, families, and unrelated individuals are based on all households, families, and unrelated individuals, respectively. The medians for people are based on [...]
Glossary: Race (U.S. Census Definition)
From the U.S. Census definition: The race of individuals was identified by a question that asked for self-identification of the person’s race. Respondents were asked to select their race from a “flashcard” listing racial groups. The population is divided into five groups on the basis of race: White; Black; American Indian, Eskimo or Aleut; Asian [...]
Keene State Quantitative Literacy Outcomes (and Mapping Codes)
The following tags will be used on posts to indicate the programmatic student learning outcomes they support: SLO-ADS: Apply basic methods of descriptive statistics. SLO-UAS: Use appropriate software to create charts, tables, spreadsheets. SLO-IVD: Read and interpret visually represented data. SLO-DGM: Distinguish among various types of growth models. SLO-CRP: Critically read and interpret quantitative problems. [...]
Graphing Longitudinal Comparisons
How has student borrowing for education changed over time? Here’s one look at that question, shown as a bar chart: Visually the impact is striking — but as with all comparisons we need to make sure we actually understand the terms of the comparison. First, you need to ask what is being measured. When longitudinal [...]
Top and Bottom Quintile
In the COMPARABLE framework, the “Question of Edges” is a placeholder to remind us that measures of central tendency such as mean, median, and mode are helpful, but only tell us so much. One way to get a sense of the distribution of values is to use quintiles. With quintiles, we start out by imagining [...]
Predicting with Percentages (Review)
Quick review of our idea of “representativeness”: When we hear a percentage (For example, 41% of college students are male vs. 59% female) used to advance a theory (fewer men want to go to college) we can make predictions based on assumptions (if the reason for the non-representation is lack of applicants then SAT participation [...]
Margin of Error (Is my comparison the result of chance?)
a. Focusing mainly on the idea of survey-based comparison. If Obama is beating Romney in the polls on the edge of MoE, what can we say? What can we not say? b. Show how this applies longitudinally as well – if Obama’s approval rating increases, but the increases is within MoE, what can we say? [...]
Cut-points and Specificity vs. Sensitivity
a. A cut-point is any point on a continuous scale we use to define a separation between states or conditions. b. Examples: High blood pressure, Failing grades, Psychological conditions based on tests, Recessions. c. Cut-points aren’t arbitrary (usually). But they always involve some non-numerical judgment on what is important. d. In the context of comparison, [...]
Percent vs. Percentiles
a. Pretty standard – getting students to understand what the difference is between these, and when to use each. b. Example: On the retest I jumped from the 40th percentile to the 90th. What does that mean? What does that not mean?
The Black Art of Choosing Your Denominator
a. Example: The rich pay a larger percentage of tax revenue than anyone else vs. The rich pay a larger percentage of their income than anyone else. b. Dueling percentage redux:
Protected: Answer: Music Sales
There is no excerpt because this is a protected post.
Question: Corporate Psychopathy
In a widely reported study, psychologists found the following: In this study, we had a unique opportunity to examine psychopathy and its correlates in a sample of 203 corporate professionals selected by their companies to participate in management development programs. The correlates included demographic and status variables, as well as in-house 360° assessments and performance [...]
A Sample Assignment Weighting for this Class
To get an A or B in this class, the student must Come to class prepared and participate (20% of grade): Reading quizzes to test preparation (10%) Participation points (awarded for engaged attendance) (10%) This class relies on student participation to work. Missing more than three classes is grounds for failure. Early in the year [...]
![newpic[1]](http://www.makingfaircomparisons.us/wp-content/uploads/2012/05/newpic1-300x276.jpg)
Question: Mortgage vs. Rent
![statuatory[1]](http://www.makingfaircomparisons.us/wp-content/uploads/2012/05/statuatory1-300x120.png){kind=small}
Question: Weighted Tax Average
The above graph shows average taxes for 15 countries. Notice the difference between the straight average, and the average weighted by population (25.3 vs. 27.2). 1. Do a mental experiment to figure out the following: Does this difference between the weighted average and the straight average mean that a smaller country (or number of smaller [...]
![blog_gallup_gay_marriage_trend[1]](http://www.makingfaircomparisons.us/wp-content/uploads/2012/05/blog_gallup_gay_marriage_trend1-300x121.jpg){kind=small}
Question: Support for Same-Sex Marriage
Here are the long term trends in support for same-sex marriage, as pulled from a recent Gallup poll: Questions: 1. The graph shows an increase in support using 1996 as a baseline year. What year would you have to use as a baseline year to show a decrease in support for gay marriage. Draw a [...]
Questions Following Weighted Means and Standardization
1. Look at the following graph: Notice the difference between the average tax weighted by population, and the average tax. Make up a set of six imaginary countries with different populations and tax rates where the weighted average tax is less than the unweighted average tax. What trends do you notice? 2. 3. A 2006 [...]
Question: Predicting Marriage
A longitudinal study with 95 newlywed couples examined the power of the Oral History Interview to predict stable marital relationships and divorce. A principal-components analysis of the interview with the couples (Time 1) identified a latent variable, perceived marital bond, that was significant in predicting which couples would remain married or divorce within the first [...]
Question: Random vs. Scientific
A recent headline: Here’s how the ACS is implemented (from Wikipedia): The ACS has an initial sample of approximately 3 million housing unit addresses and group quarters in the United States, with sample selected from all counties and county-equivalents, American Indian and Alaska Native area, and Hawaiian Homeland, and in Puerto Rico annually. Data are collected primarily by mail, with follow-ups by [...]
What to Ask a Chart
Obesity Infographic
3+C: White Working Class Voting Patterns
Haidt settles on the definition of the white working class offered by Ruy Teixeira and Alan Abramowitz, which includes white people without college degrees who are currently employed. (Excluding retirees and homemakers makes some difference, but not a lot. Focusing on education to the exclusion of income matters more; the resulting “white working class” [...]
Probability of Death
3+C Example: Where People Check Cell Phones
This tells us: In general, younger people check cell phones in a wider array of situations More people check their phone in bed than do in houses of worship One place where middle-aged people check their phones more than other demographics is at meals with others. It does not tell us: Margin of error. We [...]
3+C: Metro Areas and College Degrees
![561px-Educational_attainment[1]](http://www.makingfaircomparisons.us/wp-content/uploads/2012/07/561px-Educational_attainment1-280x300.jpg)
3+C: College Attainment
PI: Genevieve’s Career Goals
At a dinner party this weekend, a friend introduces you to a woman named Genevieve. He tells you that Genevieve recently graduated from Smith College with a B.A. in Philosophy, where she was active in the Occupy movement and edited a literary magazine. You’re interested in talking to Genevieve about Hegel, the subject of her [...]
Statistics of Climate Change
The neat thing about this explanation is it explains a lot of non-climate stuff as well.
Berkey-Caulfield Class: Grading Individual Contribution
Some notes about individual contribution: A zero does not mean you did nothing, it means that you did not pull your weight. Grading contribution to group on a scale of 0-100: 100: exemplary contributor 90: strong contributor 85: average contributor 70: light contributor 0: Free-rider Sample computations for project score at 70/30 breakdown: 85% on [...]
Activity: Smoking and Alzheimer’s
A friend tells you about an article says that those that smoke are at less risk for Alzheimer’s, a degenerative mental disease which afflicts 1 in 10 people over age 65 and nearly half of people over 85. As evidence, the person points to two studies. The first looks at the entire U.S. population, and finds [...]