A. What is the chance that the sun will come up tomorrow?
B. ŒWhat is the chance that, while you are sleeping, your bed will
C. turn to chocolate?
D. ŒWhat is the chance that it will rain today?
E. ŒWhat is the chance that the temperature will reach at least 70°F
F. What is the chance that you will have homework tomorrow
G. Come up with one of your own events.
Algebra 2 Warm up
Directions: Place each event on the scale according to
how likely it is to happen
The chance or likelihood of an event happening
A probability is a number between 0 and 1.
0 = impossible
1 = Certain
Who invented Probability?
1600’s – Games of Chance
Theoretical vs. Experimental
• Theoretical Probability - What we expect to
happen based on mathematics.
• Experimental Probability – What actually
The great number of times you perform an
experiment, the closer the 2 become.
How do we calculate
• Probability =
• Ex: Probability of getting HEADS in a coin toss.
Probability of getting the sum of 7
when rolling 2 dice:
1. 2 dice are rolled.
a. Find the probability that the sum of the numbers is 10
b. The sum is at least 10
2. A letter is selected at random from the word TRIANGLE.
a. Find the probability of selecting a vowel
b. Find the probability of selecting a letter between F and Q.
• The probability of an event NOT happening.
• Remember the total probabilities add to 1.
Let P(A) = probability of event A
1 - P (A) = probability of event A NOT happening