Basic Probability
Dave has a spinner with 5 equal sections, each a different color. After only 10 spins, the pointer had landed on red 4 times. If he spins the spinner 1,000 times, what is the probability of it landing on red based on the 10 spins he did?
400/1000 = 0.4 = 40%
You are trying to decide what to wear to school. You know you have a green pair of pants, a red pair, and a blue pair. You also have a brown shirt, a plaid shirt, and a yellow shirt. How many different outfit combinations can you make?
9
Define "probability."
It is the probability of what should occur.
The classic wood carousel at an amusement park has 32 jumping horses and 16 standing horses. What is the probability of randomly selecting a jumping horse?
1/2, or 0.50, or 50%
What is the probability of taking a red marble out of a bag of 3 blue marbles, 4 green marbles and 8 red marbles?
8 out of 15
What is the number of possible outcomes for spinning one spinner with 8 equal sections and another spinner with 6 equal sections?
48 possible outcomes
What does it mean when a probability is certain to happen?
An event will 100% happen
How likely is it that a six-sided die is tossed and lands on 3?
Unlikely
What is the probability of rolling two odd numbers in a row with a 6-sided die?
1/4, or 0.25, or 25%
A letter tile is randomly selected from a bag, recorded, and replaced 100 times. The results are listed below. What is the probability of selecting the letter "E"? A = 16 E = 11 I = 29 O = 19 U = 25
11/100 or 0.11, or 11%
Amiya and Keyshawn are candidates for class president of the 7th grade. Ajaye, Chishon, and Laura are candidates for vice president. How many winning combinations are possible for president and vice president?
6
Define "dependent" events.
When one event occurs and that item is not replaced before the second event occurs.
How likely is it that a six-sided die is tossed and it lands on 8?
Impossible
There are 3 red marbles, 2 green marbles, and 1 yellow marble in a box. One marble is taken out and not replaced. A second marble is then taken out. What is the probability both marbles that were taken out are red?
1/5, or 0.20, or 20%
Pedro recorded the types of birds that visit his bird feeder. Based on the results below, what is the probability the next bird will be a chickadee? Woodpecker = 3 Chickadee = 5 Cardinal = 1 Sparrow = 13 Blue Jay = 3
1/5, or 0.20, or 20%
Define "independent event."
When one event occurs and the item is replaced before the second event occurs.
How likely is it that a six-sided die is tossed and lands on any number 1-6?
Certain
Erica spins a spinner with 5 equal sections numbered 1-5 and she spins another spinner with 5 equal sections with the letters A-E. What is the probability she will spin a 4 and a B?
1/25 or 0.04, or 4%
A six-sided die is thrown 4 times. What is the probability of rolling an even number all 4 times?
1/16 = 0.0625= 6.25%
What is the probability of rolling three 4's in a row on a six-sided die?
1/216
Describe the difference between events that are certain, likely, equally likely, unlikely, or never going to happen.
Certain would be 100% of the time, likely is anything greater than 50% of the time, equally likely is exactly 50% of the time, unlikely is anything less than 50% of the time, and never is anything that has a 0% chance of occuring.
How likely is it that a six-sided die lands on 2 and a coin lands on heads?
Unlikely