Skip to main content

Posts

Showing posts with the label cars

Flowingdata's Car Costs vs. Emissions story

FlowingData shared some interesting info on how much cars cost version their environmental footprint .  TL;DR: Low emission cars tend to be cheaper in the long run. Hooray for the free market! The data is also available via the New York Times , along with a much more in-depth conversation about the actual cost of high/low emission cars, but it is behind a paywall. The original data, presented in a fun (nerd fun) interactive website , is available here.  How to use it in class: 1) It's a correlation! Each car model is a dot with two related data points: Average cost per month and average carbon dioxide emissions per mile.  2) It's Simpson's Paradox! Note how electric cars (yellow cloud all have similar emissions, but the average cost per month varies. Same for Diesel cars. Overall, you still see the positive correlation in the data, but if you break it down by class of car, the correlation isn't present for every level. 

My favorite real world stats examples: The ones that mislead with real data.

This is a remix of a bunch of posts. I brought them together because they fit a common theme: Examples that use actual data that researchers collected but still manage to lie or mislead with real data. So, lying with facts. These examples hit upon a number of themes in my stats classes: 1) Statistics in the wild 2) Teaching our students to sniff out bad statistics 3) Vivid examples are easier to remember than boring examples. Here we go: Making Graphs Fox News using accurate data and inaccurate charts to make unemployment look worse than it is. Misleading with Central Tendency The mean cost of a wedding in 2004 might have been $28K...if you assume that all couples used all possible services, and paid for all of the services. Also, maybe the median would have been the more appropriate measure to report. Don't like the MPG for the vehicles you are manufacturing? Try testing your cars under ideal, non-real world conditions to fix that. Then get fined by the EPA. Mis...

Improper data reporting leads to big EPA fines for Kia/Hyundai

On November 3, 2014, Hyundai and Kia were fined a record-setting $100 million for violating the Clean Air Act. In addition, they were fined for cooking their data and misreporting their fuel economy, using the unethical (cherry-picking) techniques described below by representatives of the federal government: " "One was the use of, not the average data from the tests, but the best data. Two, was testing the cars at the temperature where their fuel economy is best. Three -- using the wrong tire sizes; and four, testing them with a tail wind but then not turning around in the other direction and testing them with a head wind. So I think that speaks to the kinds problems that we saw with Hyundai and Kia that resulted in the mismeasurement." Video and quote from Sam Hirsch, acting assistant attorney general.    Here is EPA's press release about the fine .  How to use it in class: -Hyundai and Kia cherry-picked data, picking out the most flattering data but not the...