"Calculating Probability Using Drawing Tree Diagrams and Lists" PPT courseware

Description

"Calculating Probability Using Drawing Tree Diagrams and Lists" PPT courseware

learning target

1. Be able to use the method of drawing tree diagrams to find the probability of simple events;

2. Be able to use the list method to find the probability of simple events.

Review the past and learn the new

1. The probability and expression of three events:

①The probability of an inevitable event occurring is 1 and is recorded as P (inevitable event) = 1;

②The probability of an impossible event occurring is 0 and is recorded as P (impossible event) = 0;

③If A is an uncertain event, then 0＜P(A)＜1

2. Two characteristics of equally likely events:

(1) There are only a limited number of results;

(2) Each outcome is equally likely to occur.

How to find the probability of equally likely events-----dendrogram list method

What are the advantages of using list method and tree diagram method to find probability?

Tree diagrams or tables can be used to clearly represent all possible outcomes of an event, making it easier to find the probability of certain events.

What should we pay attention to when calculating probability using tree diagram and list methods?

When using tree diagrams and lists to find probabilities, it should be noted that the likelihood of various results must be the same.

Dialysis of typical cases

Two opaque bags A and B contain balls that are the same except for the color. Bag A contains one red, blue, and yellow ball, and bag B contains one red and blue ball. They are randomly selected from each bag. If a ball is drawn on the ground, what is the probability that the two balls are of the same color?

Two dice are thrown at the same time. After settling, what is the possible sum of the points on the up side of the two dice? Which number has the highest probability? What number is the least likely?

Analysis: If you draw a tree diagram, you need 42 arrows, which is too troublesome, so it is simpler to use the list method.

Practice in class

1. Integers from 1 to 6 are written on 6 cards respectively. One card is randomly selected and replaced, and another card is randomly selected. Then, the probability that the number taken out for the first time can evenly divide the number taken out for the second time. It's 7/18.

2. A car passing through an intersection may continue to go straight, or it may turn left or right. If these three possibilities are the same, when three cars pass through this intersection, find the probability of the following events:

(1) All three vehicles continue to go straight;

(2) Two cars turn right and one car turns left;

(3) At least two vehicles turn left.

Summary of this lesson

Tree diagrams or tables can be used to clearly represent all possible outcomes of an event, making it easier to find the probability of certain events.

When the test involves two steps, the list method is more convenient. Of course, the tree diagram method can also be used at this time. When the test involves three or more steps, the tree diagram method is convenient.

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"Calculating Probability Using Drawing Tree Diagrams and Lists" PPT Courseware 2:

"Calculating Probability Using Drawing Tree Diagrams and Lists" PPT Courseware 2 Review Review What methods of calculating probability did you learn in the previous class? 1. Drawing tree diagrams 2. Lists Teaching objectives 1. Be proficient in using tree diagrams and lists to calculate the probability of random events; 2. By drawing tree diagrams and columns..

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Update Time: 2024-11-20

This template belongs to Mathematics courseware Qingdao Edition Ninth Grade Mathematics Volume 2 industry PPT template

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