Modeling eBay auctions
Sometimes modeling a whole dataset suggests trends that disagree with models on separate parts of that dataset. This is known as Simpson's paradox. In the most extreme case, you may see a positive slope on the whole dataset, and negative slopes on every subset of that dataset (or the other way around).
Over the next few exercises, you'll look at eBay auctions of Palm Pilot M515 PDA models.
| variable | meaning |
|---|---|
price |
Final sale price, USD |
openbid |
The opening bid, USD |
auction_type |
How long did the auction last? |
auctions is available; dplyr and ggplot2 are loaded.
This exercise is part of the course
Intermediate Regression in R
Hands-on interactive exercise
Have a go at this exercise by completing this sample code.
# Take a glimpse at the dataset
___
# Model price vs. opening bid using auctions
mdl_price_vs_openbid <- ___
# See the result
mdl_price_vs_openbid