"Using Samples to Estimate Populations" PPT courseware

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"Using Samples to Estimate Populations" PPT courseware

When examining the population variance, if the population to be examined contains many individuals, or the examination itself is destructive, in practice, the sample mean (or variance) is often used to estimate the population mean (or variance).

1. (4 points) In order to understand the vision status of junior high school students in the city, the Zhuzhou City Caring for the Next Generation Working Committee randomly selected 500 students from 30,000 junior high school students in the city for a vision test. It was found that 100 of them had poor vision. Then It can be estimated that among the 30,000 junior high school students in the city, about ()

A． 100 people

B． 500 people

C. 6,000 people

D. 15,000 people

2. (4 points) A school carried out the "Save Every Drop of Water" activity. In order to understand the water saving situation in the past month since the activity was launched, 20 students were selected from 400 students in the eighth grade to calculate the water saving situation of their families in one month as follows: As shown in the table: Please estimate that the total amount of water saved by the families of these 400 students in a month is approximately ()

A． 130m3B． 135 m3C． 6.5m3D． 260 m3

12. (16 points) According to market research, a certain type of high-quality watermelon with a mass of (5±0.25) kg is the most popular. In order to control the quality of watermelons, the Institute of Agricultural Sciences used two planting techniques, A and B, to conduct experiments. Now randomly select 20 watermelons from each of the watermelons grown by these two techniques, and record their quality as follows

(Unit: kg):

A． 4.1　4.8　5.4　4.9　4.7　5.0　4.9　4.8

5.8　5.2　5.0　4.8　5.2　4.9　5.2　5.0

4.8　5.2　5.1　5.0

B． 4.5　4.9　4.8　4.5　5.2　5.1　5.0　4.5

4.7　4.9　5.4　5.5　4.6　5.3　4.8　5.0

5.2　5.3　5.0　5.3

(1) If the product with a mass of (5±0.25)kg is a superior product, complete the following table based on the above information:

(2) Please evaluate the two technologies A and B from the three aspects of the number of excellent products, average and variance respectively; from the perspective of market sales, which planting technology do you think is better to promote?

(2) From the perspective of the quantity of high-quality products,

Because the number of high-quality watermelons grown with technology A is greater, technology A is better;

From an average point of view,

Because the average mass of watermelons grown with technology A is closer to 5 kg, technology A is better;

From a variance perspective,

Because the quality variance of watermelons grown with technology B is smaller, the quality of watermelons grown with technology B is more stable;

From a marketing perspective,

Because high-quality products are more popular, the number of high-quality watermelons grown with technology A is larger, and the average quality is closer to 5 kg, so it is more suitable to promote technology A.

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"Using Samples to Estimate Populations" PPT Courseware 2:

"Using Samples to Estimate the Population" PPT Courseware 2 Case: There are 50 high-quality apples in a box, and 2 are randomly picked out from it. Use the average mass (g) of these 2 apples to estimate the average mass of each apple in the whole box. Do you think this estimate is accurate? How about taking any 5? Take any 10..

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Update Time: 2024-09-08

This template belongs to Mathematics courseware Hebei Education Edition Ninth Grade Mathematics Volume 1 industry PPT template

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