4.3 Making Predictions

4.3 Making Predictions

By Christina Sandoval

Unit 4, Lesson 3

I can make predictions based on theoretical and experimental probabilities.

Making Predictions & Probability

What is probability? Let’s review - 

• Remember, that probability is the ratio of the number of ways an event can occur to the total number of outcomes.

• The value is between 0 and 1!

• The value can be expressed as a fraction, decimal, or percent.

• A probability of 1 means the event is certain to occur.

• A probability of zero means that the event will certainly not occur.

• The closer the value is to 1, the more likely the event will occur. 

4.3 Making Predictions

Probabilities can be used to make predictions about future events.

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Step 1: Find the probability (ratio).

Step 2: Multiply the probability ratio by the total amount.

Step 3: Simplify when necessary!

Algebra Readiness

Unit 4, Lesson 3: Making Predictions

Making Predictions & Probability

Megan is running for 8th grade class president. She asks everyone in her math class how they plan to vote and finds out that 15 out of 25 (or 15/25) students will vote for her. The probability that Megan will get a vote from the students in her math class is ⅗. She can use this probability to make a prediction of the overall results of the election.

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If there are 125 students in the 8th grade class who will vote, you can calculate how many total votes Megan will receive by multiplying ⅗ by 125. How many votes is Megan likely to receive?

Making Predictions & Probability

Megan is running for 8th grade class president. She asks everyone in her math class how they plan to vote and finds out that 15 out of 25 (or 15/25) students will vote for her. The probability that Megan will get a vote from the students in her math class is ⅗. She can use this probability to make a prediction of the overall results of the election.

​

If there are 125 students in the 8th grade class who will vote, you can calculate how many total votes Megan will receive by multiplying ⅗ by 125. How many votes is Megan likely to receive?

Multiple Choice

What is the correct expression to help us find the probability of votes Megan is likely to receive?

• $$\frac{3}{5}\cdot\frac{1}{125}$$  

• $$\frac{3}{5}\cdot\frac{125}{1}$$  

Making Predictions & Probability

Megan is running for 8th grade class president. She asks everyone in her math class how they plan to vote and finds out that 15 out of 25 (or 15/25) students will vote for her. The probability that Megan will get a vote from the students in her math class is ⅗. She can use this probability to make a prediction of the overall results of the election.

​

If there are 125 students in the 8th grade class who will vote, you can calculate how many total votes Megan will receive by multiplying ⅗ by 125. How many votes is Megan likely to receive?

Multiple Choice

How many votes is Megan likely to receive?

• $$\frac{375}{5}\ votes$$  

• 75 votes 

• $$\frac{5}{375}\ votes$$  

• 5 votes

Making Predictions & Probability

Mrs. Becker drives past the Route 50 Drawbridge light every morning on the way to work.  8 out of 10 times, that traffic light is red.  There are only 25 days of school left, how many of those days should she expect to get stopped at that light?

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You'll submit your answer on the

next slide. ​

Multiple Choice

 Mrs. Becker drives past the Route 50 drawbridge light every morning on the way to work.  8 out of 10 times, that traffic light is red.  There are only 25 days of school left, how many of those days should she expect to get stopped at that light?

• $$\frac{200}{10}\ days$$  

• 200 days

• 20 days

• $$\frac{10}{200}\ days$$