"Changing Trends of Random Phenomenon" PPT courseware

Description

"Changing Trends of Random Phenomenon" PPT courseware

learning target

Use the coordinate system to study the changing trends of certain random phenomena and the correlation between random phenomena.

New course introduction

In the objective world, some correlations between variables in interconnected random phenomena can be determined, such as linear functions, quadratic functions, etc. Sometimes, after one randomly generated data is determined, another value related to it cannot be determined. Completely certain. For example, the relationship between grain yield and the amount of fertilizer applied to crops. Within a certain range, the more fertilizer applied, the higher the crop yield will be. However, the yield of crops cannot be completely determined by the amount of fertilizer applied.

collaborative inquiry

In order to study the relationship between the height and weight of teenagers, the mathematics interest group of Class 1 of Grade 9 randomly selected 13 boys from the class and measured their heights (unit: cm)

and body weight (unit: kg), we get two sets of data in the following table:

Straight line b can more closely represent the distribution of points in the list than straight line a, so straight line b can better reflect the correlation between the weight and height of the boys in the sample than straight line a, that is, the weight increases linearly with height. growth trend.

Dialysis of typical cases

A supermarket randomly selected the daily profit and daily turnover for 12 days, as shown in the following table:

(1) In the rectangular coordinate system, the horizontal axis represents turnover, the vertical axis represents daily profit, and the corresponding data points of 12 number pairs are described;

(2) In the coordinate system, a straight line is drawn, which can approximately reflect the correlation between daily profit and turnover;

(3) If the daily turnover of this supermarket is estimated to be 160,000 yuan, what is the approximate daily profit?

Practice in class

In order to understand the relationship between the tree height and the diameter at breast height of a certain tree, Shanqing Forestry Farm randomly selected ten trees, counted their ages and measured them. Their diameter at breast height results are shown in the table below,

(1) In the Cartesian coordinate system, trace the points corresponding to each ordinal number pair (diameter at breast height, tree age) in the table.

(2) In the rectangular coordinate system, draw a straight line so that it can approximately reflect the correlation between diameter at breast height and tree age.

(3) What is the approximate diameter at breast height of this tree that is estimated to be 40 years old? .

Solution: (1) As shown in the figure

(2)As shown in the figure

(3) The diameter at breast height of a 40-year-old tree estimated from a straight line is approximately 38 cm.

Summary of this lesson

Although some of the correlations between variables in interconnected random phenomena cannot be completely determined, in some cases, after a randomly generated data is determined, a linear function straight line can be used to estimate the approximate value of another variable.

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"Changing Trends of Random Phenomenon" PPT Courseware 2:

"Changing Trends of Random Phenomenon" PPT Courseware 2 Situation Introduction Guess: Do you think there is a relationship between the height and weight of teenagers? Suppose you were asked to study the relationship between height and weight in adolescents. What would you do? Experimental research: 10 male students from our school were randomly selected...

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Update Time: 2024-07-30

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

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