(1) Experience the significance and function of distribution through examples; (2) In the process of representing sample data, learn to list the frequency distribution table and draw the frequency distribution histogram and frequency line graph; (3) Experience the characteristics of frequency distribution histogram, frequency line graph and stem leaf graph through examples, so as to properly select the above methods to analyze the distribution of samples and make an accurate overall estimate.

Two. Learning focus

3. Learning disabilities

The distribution of the population can be estimated by the frequency distribution of the samples.

4. Review and introduction of learning process (1)

(1) What is the core problem of statistics?

(2) What are the common methods of random sampling?

(3) What is the purpose of sampling and collecting data?

(2) Self-study program

1. What statistics have we learned? What kind of data are different statistical charts suitable for describing?

2. How to list the frequency distribution table?

3. How to draw the histogram of frequency distribution? What are the basic steps?

4. What is the ordinate of the frequency distribution histogram?

5. What is the area of the small rectangle in the frequency distribution histogram?

6. What is the sum of the areas of small rectangles in the frequency distribution histogram?

(3) Self-test before class

1. randomly select 20 apples from a pile, and the data distribution table of their mass (unit: g) is as follows:

Grouping [90, 100] [100,10] [10, 120] [120,/kloc-0. In this pile of apples, the number of apples whose mass is not less than 120g accounts for about _ _ _ _ _ _% of the total number of apples. 2. Regarding the histogram of frequency distribution, the following statement is correct: () A. The height of the histogram indicates the frequency of individuals in the group in the sample. B. The height of the histogram indicates the frequency of taking a certain number. The height of the histogram represents the ratio of the frequency of individuals in the group to the distance of the group. The height of the histogram represents the ratio of the frequency of individuals in the group to the distance of the group. 3. Known samples:10,8,6,65438+. 10, 12, 1 1, 7,8,9, 1 2,9, 10,1/kloc.

Question 1. What do you think needs to be done to reasonably determine this standard? 2. How to analyze the data? According to these data, can you get other information about water consumption? Knowledge collation: 1. The concept of frequency distribution: frequency distribution: frequency: frequency:

2. Draw the histogram of frequency distribution: (1). Find the scope: (2). Determine the interval and number of groups: (3). Group the data (4). Column frequency distribution table (5). Draw the histogram of frequency distribution:.

1. The average monthly water consumption is 2.5? What is the frequency between 3?

2. What is the maximum monthly water consumption range?

3. How often is the average monthly water consumption less than 4.5?

4. The area of the small rectangle =?

5. The sum of the areas of small rectangles =?

6. If it is hoped that more than 85% of the residents will not exceed the standard, what is the standard?

7. What are the advantages and disadvantages of histogram?

Example explanation: The grouping frequency of 1 data with 50 samples is as follows: [12.5, 15.5] 3 [15.5, 18.5]8[ 18.5,. 24.5)11[24.5,27.5]10 [27.5,30.5] 5 [30.5,33.5] 4 (1) lists the frequency distribution table of the samples; (2) draw a histogram of frequency distribution; (3) According to the histogram estimation of frequency distribution, what percentage of data falls within [15.5,24.5]? (4) What percentage of data is less than 2 1.5?

3. Question of frequency distribution line chart and population density curve 1: How to get the frequency distribution line chart? The concept of frequency distribution line chart;

Question 2: What will happen to the histogram of frequency distribution when the sample size increases from 100 to 1000? What if it is increased to 10000?

The concept of population density curve;

Note: When the sample distribution histogram is used to estimate the corresponding population distribution, the larger the sample size, the more accurately the frequency distribution histogram can approximate the population density curve, that is, it can accurately reflect the distribution law of the population in each interval, that is, 1. Population distribution refers to the frequency distribution law of population value. Because the population distribution is not easy to know, we often use the frequency distribution of samples to estimate the population distribution.

4. The concept of stem-leaf diagram: the characteristics of stem-leaf diagram:

Summary: the distribution of the population is divided into two situations: when the individual values in the population are small, the distribution of the population is estimated by the stem-leaf diagram; When there are multiple individuals in the group, the sample data are grouped appropriately, and the frequency distribution of each group is used to describe the distribution of the group. The method is to use frequency distribution table or frequency distribution histogram.

Course summary:

In-class test:

1. A social investigation agency surveyed 10000 people about the monthly income of residents in a certain place, and drew the frequency distribution histogram of the sample according to the obtained data (as shown below). In order to analyze the relationship between residents' income and age, education, occupation, etc. If you want to select 10000 people by stratified sampling for further investigation, you should select people from the [25003000] (yuan) monthly income segment.

2. In order to know the eyesight of senior three students in a school, the eyesight of 200 senior three students in this school is randomly selected, and the histogram of frequency distribution is obtained (as shown in the figure). Because we accidentally lost some data, but we know that the frequency of the first four groups is equal, and the frequency of the last six groups is arithmetic progression. Suppose that the number of students in a group is A, and the frequency of vision between 4.6 and 5.0 is B, then

A+b=。 3. In the process of spot-checking product sizes, divide their sizes into several groups, [a, b] is one of them, the frequency of the individuals in this group is m, and the height of the histogram in this group is h, so ba? = _ _ _ _ _.4. In order to understand the height of middle school students, 50 boys of the same age in Yucai Middle School were measured. The results are as follows: (unit: cm):17516818017616718162172.

(1) List the frequency distribution table of samples.

(2) Draw the histogram of frequency distribution.

(3) draw a line chart of frequency distribution;