27  P-value Discussion

Settling In

Notes

In this activity, you will read an article about p-values and then discuss a set of prompts as a group. Each group will then share out some highlights of your discussion to the class.

Readings

Your instructor will assign you to one of four groups, each with a different reading. You are of course welcome to read more than only your assigned reading if you choose to! The group reading assignments are as follows:

• Reading 1: The ASA Statement on p-values
• Reading 2: Scientific method: Statistical error
• Reading 3: Moving to a World Beyond “p < 0.05”
• Reading 4: Statistical tests, p-values, confidence intervals, and power: a guide to misinterpretations

Exercises

Step 1: Review

Take a 15 minutes to do the assigned reading.

Make note of the things you found most important, the things you found most confusing, or the things you still have questions about.

Step 2: Discuss

Once everyone in your group is ready, find an empty space at the whiteboard.

You’ll discuss the following questions with your group and write down your key takeaways from your conversation on the board.

After a few minutes, rotate to the next station: respond/react to the previous responses (e.g., add a + if your group agrees) and add your own. Repeat until you’ve visited all stations.

Questions:

1. How does this reading relate to your previous knowledge about p-values?
2. Was anything that you learned from the reading particularly surprising?
3. What are some of the ways in which p-values are often misinterpreted and/or misused?
4. What suggestions does the article offer in terms of how p-values should be used?
5. Does the article provide any suggestions in terms of other tools that we should use instead of or in addition to p-values?
6. What are your main takeaways from the reading?

Step 3: Share out

Designate someone from your group who will share the highlights of your discussion with the full class!

Wrap Up

• PS 8 due tonight
• Reminders:
  • If you miss class on a project day, it’s your responsibility to communicate with your group, find out what you missed, and make equivalent contributions outside of class. If missing class on project days becomes a pattern, it will impact your project grade.
  • Your final project grade will reflect your individual engagement and contributions to the project. You are not expected to be perfect. Rather, you should put effort, attention, and reflection into the following areas:
    • communication
      • contributing to group discussions
      • including all other group members in discussion
      • creating a space where others felt comfortable sharing ideas and mistakes
      • communicating with your group outside class
    • report contributions
      • contributing to the content / analysis in the report
      • contributing to the writing of the report
      • contributing to the editing of the report