PROBABILITY

Probability of an Event…..

Example….. What is the probability of rolling a “3” on a six sided die? Answer…… There is one “3” on a die and there are six sides.

Example…… Use the figure to the right. Suppose you throw a dart without looking where it lands on the dart board. What is the probability that it will land on a shaded square?

Answer…… There are 8 shaded squares. There are 20 total squares.

Example…… What is the probability that it will NOT land on a shaded square? Answer…… There are (20-8) or 12 unshaded squares.

Example…… What is the probability of selecting a queen out of a standard deck of 52 cards? Answer…… There are 4 queens in the deck. There are 52 cards in the deck.

Example…… An urn contains 3 blue balls, 5 red balls, and 2 orange balls. A. Find Find Answers…… A. B. C.

Fundamental Counting Principle…. If one event can occur “m” ways and a second event can occur “n” ways, then total number of ways both events can occur is

Example…… Katie has 2 pairs of pants, 4 shirts, and 3 pairs of shoes that can all match up and make an outfit. How many different outfits can Katie make? Answer….. (2)(4)(3) = 24

Example…… An urn contains 3 red and 5 blue marbles. Find the probability of selecting 2 blue marbles in a row if you do not replace the 1 st one after it is selected. Answer…… You have 5 BLUE marbles. You have 8 TOTAL marbles.

Example: Titanic 1st Class 2nd Class 3rd Class Survived Died P(3 rd class)P(survived) P(1 st class)P(died)

Example…… A single card is drawn from a deck. Find a. P(black ace) b. P(spade or diamond) Answer: a. b.

Worksheet….