Marginal and Conditional Probabilities_{}
What are the chances of choosing grape?
Def: Marginal Probability—the probability of a single event without consideration of any other event.
Def: Conditional Probability—the probability that an event will occur given that another event has already occurred.
_{}probability of A given that B has occurred
Compute with Class Grape Data

Row by Window 
Middle Row 
Row by Door 
Total 
Grape 




Not Grape 




Total 




P(middle row) = ?
P(not grape) = ?
P(not grape_{}middle row)
P(middle row_{}not grape)
**Worksheet**
**Monty’s Dilemma**