Unit 2 Task 3: Validation

Published

April 2, 2025

Background

When you hear the word “relationship” what is the first thing that comes to mind? Probably not baseball. But a relationship is simply a way to describe how two or more objects are connected. There are many relationships in baseball such as those between teams and managers, players and salaries, even stadiums and concession prices.

The graphs on Data Visualizations from Best Tickets show many other relationships that exist in baseball.

It is rare for an analysis to rely solely on one table. In fact, that is the whole point of a relational database: to quickly and easily tie tables together. Many students have already learned how to join tables using SQL. This assignment gives you practice joining tables using Python Pandas code. Students inevitably ask, “if I can do the same thing in both languages, why/when would I chose one over the other?”. This thread has some good thoughts on the topic.

Client Request

For this project you will use Python pandas code to join (a.k.a. merge) tables and perform additional manipulations. You will still need to connect to the database to pull the data in, but all the filtering, calculating, joining, etc. should be done with Python pandas (or polars).

Data

Note

This project will use the Lahman Baseball Database. In order to complete this project, you will need to download the database and save it inside the DS250 folder (hopefully you have a folder dedicated to this class) next to the .qmd file you will be using for this assignment. Note: Right click the ‘Download’ link and select “Save Link As” to download the data to your computer.

Download: lahmansbaseballdb
Information: Lahman Data Dictionary
Setup Instructions: See SQL Setup

Readings

Complete these readings before we cover the material in class. This will help you retain the material and make the class period more engaging - not less.

In other words, if an assignment is due on Wednesday, we will cover the material needed to complete the assignment on Tuesday. Therefore, you should complete the readings on Monday (or anytime before class on Tuesday).

Optional

  • P4DS: CH13 Exploratory Data Analysis Skim to see many different possible geoms to use depending on the data types and to see some of the commands from CH4 again.
  • [P4DS: CH4 Data Transformation](https://aeturrell.github.io/python4DS/data-transform.html#) as review

Questions and Tasks

Download the template for this task.

  1. Write an SQL query that pulls in the the salaries table and the collegeplaying table (and any other tables you might need) and store them in pandas dataframes. Combine the dataframes to create a list of baseball players who attended BYU-Idaho. The new table should contain five columns: playerID, schoolID, salary, and the yearID and teamID associated with each salary.

  2. Pick any two baseball teams and compare them using a metric of your choice (average salary, home runs, number of wins, etc). Be creative! Write an SQL query to read in the table(s) you need, then use pandas to manipulate the data. Finally, make a graph using Lets-Plot to visualize the comparison. What do you learn?

Submission:

When you have completed the report, you will need to follow this process to submit your work:

  1. Have this assignment’s template/quarto file open in VS Code and nothing else
  2. Click Preview Button in VS Code in the top right of the screen
    1. This will render the project but also entire course work portfolio into HTML files for review
    2. Confirm everything displas as you would like it to
    3. How you see it will be how it is viewed for grading
    4. If there is an error in any cell of the quarto files, the rendering will stop and you will need to fix the error before rendering again (if you get stuck post your error in Slack)
  3. Once the report is confirmed close the preview and open a VS Code Terminal
    1. click Terminal in the top menu bar and then New Terminal
  4. Type the following in the terminal quarto render
    1. Then drag and drop this assignment into the terminal. This will add the file path to the terminal command
    2. Press Enter
  5. This will render the project into a HTML file in the same location as the .qmd file
  6. To locate the file in VS Code
    1. Right click on the file in the file explorer and select Reveal in File Explorer(Win) or Reveal in Finder(Mac)
  7. Upload HTML file into Canvas

Deliverables:

Use this task’s template to submit your Client Report.

Answers to the questions | tasks. Each should include a written description of your results, code cells with comments, charts and/or tables.

Note

Your report should be written in quarto markdown files and rendered to an HTML File. Upload the HTML file in Canvas. (Do not submit the .qmd file)

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