Intro to Basic Probability

Probability is the chance of something you want to happen, happening.

example: there is a 50% chance of flipping heads on a quarter.

To find probability, you make a fraction.

top = number of times what you want to happen can happen.

bottom = total number of things that can happen.

Since there are 12 marbles in the bag, 12 goes on the bottom.

in the first example, you want red. there are 7 red marbles, so 7 goes on top.

in the 2nd example, you want blue. there are 5 blue marbles, so 5 is on top.

The answer can be given as:

- fraction (REDUCE the fraction)

- percent

- decimal

Multiple Choice

Probability can be written as ...

• a fraction
• a decimal
• a percent
• all of the above

Multiple Choice

A bag contains 5 quarters, 2 dimes, and 4 pennies. What is the probability of picking a quarter?

• 5/11
• 5/6
• 1/3
• 5

Explanation for previous question:

• there are 5 quarters, so 5 goes on the top of the fraction.

• there are 11 total coins in the bag.

• 5+2+4 = 11

• answer = 5/11

Multiple Choice

What is the probability of flipping a coin and getting heads?

• 1/2
• 1/3
• 1/4
• Never, Tails never fails.

Explanation for previous question

• one side of the coin has "heads" so 1 is the top of the fraction

• there are 2 sides on a coin so 2 is the bottom of the fraction

• answer = 1/2
  

Multiple Choice

A bag has 3 red marbles, 2 blue and 4 yellow. What is the theoretical probability of pulling a red?

• 3/10
• 3/9
• 1/9
• 1/3

Examination of previous question

• there are 3 red marbles.

• there are 9 total marbles

• 3/9 simplifies to 1/3

• answer = 1/3

Multiple Choice

What is the probability of the spinner landing on an even number?

• 1/8

• 4/8, or 1/2

• 2/8, or 1/4

• 1/3

Multiple Choice

The letters that form the word MATHEMATICS are placed in a bowl. What is the probability of choosing a "M"?

• 8/121
• 4/11
• 2/11
• 4/121

Multiple Choice

The following M & M colors are in the bowl:
4 yellow, 6 orange, 3 green, 5 blue, 2 brown
What is the probability of selecting a brown candy?

• 2/18
• 1/9
• 2/20
• 1/10

Multiple Choice

A bag contains 30 pieces of candy. There are 15 grape, 7 cherry, 3 lemon, 5 strawberry. What is the probability of drawing a lemon? (remember to simplify the fraction)

• 3
• 1/10
• 3/10
• 30%

Multiple Choice

What is the probability of rolling a cube and having it land as a six?

• 1/6
• 5/6
• 1/3
• 1/2

Multiple Choice

What is the probability that you choose blue? *simplify

5 green

6 yellow

8 blue

7 brown

• 8/26

• 4/13

• 8/25

• 1/3

Multiple Select

What is the probability of spinning a 2 on the spinner?

• 1/2

• 1/3

• 1/8

• 1/4

Multiple Choice

A die is rolled once.  What is the probability of rolling a 5?

• 1/6
• 1/3
• 2/5
• 5/6

Multiple Choice

What is the probability of spinning green?

• 1/6

• 1/4
• 1/2
• 3/4

Multiple Choice

Using a standard deck of cards, what is the probability of choosing a red card? (A standard deck has 52 cards)

• 1/2

• 1/4

• 1/3

• 1/5

Multiple Choice

Convert the fraction to a decimal.

65/100

• 0.65

• 0.0065

• 6.5

• 6.05

Multiple Choice

Convert the fraction to a decimal.

51/100

• 0.051

• 3.6

• 0.51

• 5.1

Multiple Choice

How would the fraction 2/10 be written as a decimal?

• 2.10

• 0.2

• .02

• 20

Multiple Choice

How would the fraction 9/10 be written as a decimal?

• 9.10

• 0.9

• .09

• 90

Multiple Choice

Change 32% into a decimal.

• 32
• 3.2
• .32
• .032

Multiple Choice

Change .16 into a percent.

• 16%
• 1.6%
• 160%
• .16%

Multiple Choice

Change 82% into a decimal.

• 82
• 8.2
• .82
• .082

Multiple Choice

Change .98 into a percent.

• 98%
• 9.8% 
• 980%
• .98%

Multiple Choice

Convert 0.05 to a percent

• 50%

• 0.5%

• 500%

• 5%