Preview - Sampling Distributions 2021

Introducing our Context


Here is the data, there were 22687 total traffic stops as reported by EPD. There are lots of different questions that we might want to answer based off of this data. As you know, over the past many years Police Departments have been under scrutiny for how they treat people of color, specifically black people. In the Summer of 2020, the murder of George Floyd at the hands of the police was the latest in a string of innocent black lives lost in their interactions with police (https://www.bbc.com/news/world-us-canada-52905408). The ensuing protests and the Black Lives Matter Movement have put police treatment of black Americans in the spotlight. For that reason, we will specifically focus on data about traffic stops of black drivers throughout this lesson. Let's take a look at Data from Evanston. Clearly this could be an issue for any race, or gender, or a lot of other things, but for the purpose of this lesson we'll focus specifically on black vs. non-black drivers in Evanston.

Remember, this is traffic stops by EPD from 1/1/20 - 7/23/20 broken down by race.

Race Number
White 12407
Black 6887
Hispanic 1784
Asian 1465
Unknown 144
Total 22687

See below for questions and instructions.


Questions

Please answer the questions below.

Someone looks at this data and concludes that EPD is biased against white people. Do you agree? How would you use this data to support or refute their claim?


What other information do you think is needed in order to investigate the idea that EPD is disproportionately stopping one race of driver?


Calculate the proportion of traffic stops in which the driver was black. 


Set the population proportion slider to match your answer in the previous question. When you click "setup" button and then the “take sample” button the model will take an SRS of 5 traffic stops and report the proportion of drivers who identify as black. Take a few samples. Do you get proportions close to the actual value? Explain why you do or do not.


On the next page you're going to do some work with sampling distributions. Define the term "sampling distribution" in one sentence. 


Before we get too deep into this, let's acknowledge that this is a very complicated issue. The how and why of traffic stops is complicated. Understanding that there are no right answers, what are some possible problems that exist with this data before we do anything to it?


Notes

These notes will appear on every page in this lesson so feel free to put anything here you'd like to keep track of.