Learn · Reasoning

Parlays & Expected Value

Odds, vig, EV, and parlay compounding — plus the brain moves that override the math and a 30-second check for any random-outcome purchase.

Study

LessonReasoning30 min11 pages6 question check at the end
ReasoningPage 1 of 11
x
I'll bet you a dollar

An unfair coin flip introduces the vig.

A friend says: "I'll bet you $1 the next coin flip is heads. If heads, you give me $1. If tails, I give you $1."

You'd probably take that bet or skip it depending on your mood. It's fair.

Now they say: "I'll bet you $1. If heads, you give me $1.10. If tails, I give you $1."

Suddenly it's a worse deal — you only get $1 when you win, but you lose $1.10 when you lose.

This whole lesson is about spotting it.

Back to overview