# More Variable Relations

#### rwcarroll1

##### New Member
1. Suppose a single card is selected from a standared 52 card deck. What is the probability that the card drawn is from a king?

2. Now suppose a single card is draw from a standard 52 card deck, but we are told the card is a heart. What is the probability that the card drawn is a king?

3. Did the knowledge that the card is a heart change the probability that the card was a king?

4. What is the term used to describe this result?

Any input will be assisted. Want to make sure I understand everything correctly. This is what I got:

1. A standard deck of cards has 4 kings so N(E) = 4. P(king) = P(E)= N(E)/N(S)=4/52 = 1/13

2. Probability remains the same. 1/13

3. No.

4. Disjoint. When 2 events have no outcomes in common. Two events are disjoint if they cannot occur at the same time. Another name for disjoint events is mutually exclusive events.

#### Xenu

##### New Member
4. Disjoint. When 2 events have no outcomes in common. Two events are disjoint if they cannot occur at the same time. Another name for disjoint events is mutually exclusive events.
This is wrong. Drawing a king and drawing a heart are clearly not mutually exclusive. I think the word you are looking for is independence.

#### rwcarroll1

##### New Member
Disjoint

Thanks for the post. I did some more reading and found a caution note in my text that stated "Two events that are disjoint are not independent". Thanks for taking the time to review.