The book also makes clear how much of groceries is (regulatory) arbitrage:
"We couldn't call whey butter (a cheese by-product) 'butter', so we called it 'beurre', put it next to regular butter and discounted it"
"When they de-regulated milk, we lost 20% of our gross margins"
"Wisconsin had protectionist laws for all local cheeses except for brie. We imported as much brie as we could."
"As the dollar regained strength, we could buy wine for cheap in France and introduce it to our newly educated audience"
As he lists their best innovations, most of them are rooted in some form of rule change or regulatory arbitrage. Really eye-opening to read, especially the first chapter.
• • •
Missing some Tweet in this thread? You can try to
force a refresh
Conditional probability represents the probability of B, once A has happened, defined as:
P(B|A) = P(A ∩ B) / P(A)
The formula never made sense to me because P(B|A) is not in the standard Venn diagram (my go to for probability) but it is there once you *zoom into* it
Example:
Alice comes to work with probability P(A), independently of Bob
Bob comes to work with probability P(B), independently of Alice
A and B come to work simultaneously with probability P(A ∩ B)
The universe is everything that could happen, represented by the grey box
To "condition on A", is to assume that A has happened: Alice came to work.
In this new universe, Alice is always in the office. So, our new universe is the blue box, which always has Alice.