"Stability of Frequency" Probability Preliminary PPT

Description

"Stability of Frequency" Probability Preliminary PPT

Part One: Teaching Objectives

1. Through the activities of tossing thumbtacks and coins, you will experience the processes of guessing, experimenting, collecting test data, and analyzing test results, and gain a preliminary understanding of the relationship between frequency and probability.

2. Through experiments, we can feel that the frequency of random events is stable when the number of experiments is large.

3. Understand the meaning of probability and be able to estimate the probability of certain events based on their frequency.

Frequency Stability PPT, Part 2: New Knowledge Exploration

(1) In pairs, play the thumbtack throwing game 20 times and record the data in the table below:

Xiao Ming played a total of 400 thumbtack throwing games and recorded the results of the game. He drew a line statistical chart as shown in the figure. Observing the image, what is the pattern of the changes in the frequency of the nail tip pointing upward?

Conclusion: When the number of tests is very large, the frequency of the nail tip pointing upward will swing around a constant, that is, the frequency of the nail tip pointing upward is stable.

Inquiry activities

Toss a fair coin and after the coin falls, two things will happen:

Do you think heads up and heads down are equally likely?

(1) Two people at the same table play a coin tossing game 20 times, and record the data in the table below:

(2) Accumulate the test results of the entire class, and summarize the test data into the following table:

Knowledge summary:

1. When the number of trials is large, the frequency of events will swing around a constant. This property is called frequency stability.

2. We call this numerical value that describes the possibility of event A happening the probability of event A happening, denoted as P(A).

Generally, in a large number of repeated experiments, we often use the frequency of uncertain event A to estimate the probability of event A.

Exercise 1. Which of the following events has a probability of 0 ()

A. Roll two dice, and the number "6" appears upward at the same time.

B. It took Xiao Ming 10 minutes to get from home to school, but 15 minutes to get back home from school.

C. Today is Sunday, yesterday must be Saturday

D. Xiao Ming’s walking speed is 40 kilometers per hour

Exercise 2. There are 9 balls in the pocket, including 4 red balls, 3 blue balls, and 2 white balls. Among the following events, the probability of happening is 1 ( )

A. Take a ball from the pocket and it is exactly the red ball

B. Take out 2 balls from your pocket, both are white balls

C. Take out at least one of the 6 balls that is a red ball

D. The balls taken out of the pocket are exactly 3 red and 2 white.

Frequency Stability PPT, Part 3: Class Summary

Frequency stability: When the number of trials is large, the frequency of events will swing around a constant. This property is called frequency stability.

Probability: We call this numerical value that describes the likelihood of event A happening, called the probability of event A happening, and record it as P(A).

Generally, in a large number of repeated experiments, we often use the frequency of uncertain event A to estimate the probability of event A.

The probability of a necessary event happening is 1; the probability of an impossible event happening is 0; the probability P(A) of a random event happening is a constant between 0 and 1.

Frequency Stability PPT, Part 4: Classroom Quiz

1. There are n small balls that are identical except for color in an opaque box, among which there are 6 yellow balls. Shake the balls in the box well before touching the ball each time. Pick out a ball at random and note the color before putting it back in the box. After a large number of repeated ball touching tests, it was found that the frequency of touching the yellow ball is stable at 30%, then it can It is calculated that n is approximately ()

A. 6B． 10

C． 15D. 20

2. A bag contains three colors of black, red and yellow balls that are the same except for the color. If you randomly pick out a ball from it, write down the color and put it back again. Repeat this test 500 times, and you will get 300 touches. If a yellow ball is found, the frequency with which the ball randomly picked out in these 500 trials is a yellow ball is _______.

3. There are 1 red ball, 1 green ball and n white balls in an opaque bag. These balls have no other difference except color.

(1) When n=1, a ball is randomly drawn from the bag. Are the possibilities of getting a red ball and a white ball the same?

Solution: When n=1, the number of red balls and the number of white balls in the bag are the same, so the probability of touching balls of both colors is the same.

(2) Take out a ball randomly from the bag, record its color, and then put it back. Repeat this experiment in large numbers and find that the frequency of touching a green ball is stable at 0.25. Find the value of n.

Solution: According to the meaning of the question, n=1÷0.25-1-1=2

Keywords: Free download of Beijing Normal University version of seventh grade mathematics volume 2 PPT courseware, frequency stability PPT download, probability preliminary PPT download, .PPT format;

For more information about the "Stability of Probability Preliminary Frequency" PPT courseware, please click the Stability of Probability Preliminary PPT Frequency PPT tab.

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"Stability of Frequency" Probability Preliminary PPT Download:

"Stability of Frequency" Probability Preliminary PPT Download Part One Content: Learning Objectives 1. Through the activities of tossing thumbtacks and coin toss, experience the process of guessing, testing, collecting test data, analyzing test results, etc. to initially understand the relationship between frequency and probability. 2. Through Experiment with feelings..

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Update Time: 2024-10-05

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