What is quartile sampling? Definition of quartile sampling

Quadrangular sampling, also known as conical quadrangulation, refers to a method of condensation operation in which each sample is piled into a uniform conical shape and pressed into a cone, and then divided into quarters with a cross-shaped frame.

Survey sampling of plant communities to provide raw data for vegetation research. Therefore, the choice of sampling method determines the accuracy and reliability of the final conclusions, and the traditional sampling method for vegetation research was made by Sweden as early as the 50s of the 19th century.

Scholar von Post created a sample method and is widely used. The law of unsampled land was proposed by American scholars Cottom and Curtis in the 50s of the 20th century. Not.

Plot sampling methods are used by ecologists because of their low workload, high efficiency, and ability to collect information on species competition, growth, and environmental factors, especially the midpoint quartile method.

1.The four-way fractionation sample is to pile the broken and sieved samples into a cone with a flat shovel, and then interactively pile up another cone from the bottom diagonally on both sides of the sample pile. 2.

4.The two opposite sectors are discarded, and the two sectors left are subject to the particle size and quality limits specified in the sample preparation procedure diagram;

Chinese entry name: conic quadrangle.

The sample is ground according to the requirements of the determination, passed through a sieve with a certain pore size, then mixed, tiled into a circle, divided into quarters, mixed in two opposite parts, and then divided into equal parts until it meets its own requirements.

It depends on the situation

For example, liquids: if it is easy to mix, mix well before sampling.

Solids: finely grinded, mixed and evenly sampled. Mixing can be done using the quartile method.

When the total number of samples is x and the total number of samples is x 3, each piece is sampled;

Total number of samples3 When the total number of samples x >300, the number of samples is ( x 2)+1.

There is another way.

1. Divide evenly into four equal portions.

2. Take out two portions from four portions.

3. Divide the rest into four equal portions. Buried years.

4. Take out two of the four parts.

5. Until the end.

The laboratory quartile sampling method is described in detail as follows:

1. Sampling method:

The four-way fractionation sample is to pile the broken and sieved samples into a cone with a flat shovel, and then interactively pile up another cone from the bottom diagonally on both sides of the sample pile.

The sample should not be too much for each spade, and scattered on the top of the new cone two or three times, so that it falls evenly around the new cone, and so on three times, and then from the top of the sample pile, the sample is evenly flattened from the center to the periphery.

The sample sample is placed in the middle of the flat number rental body, pressed down to the bottom, the sample is divided into four equal sectors, the two opposite sectors are discarded, and the remaining two sectors are according to the particle size and quality slippage limits specified in the sample preparation program diagram.

2. Introduction to the Book Quadrangle:

The quartile division is a kind of ancient Chinese book classification method, which refers to the method of dividing literary works into different literary genre categories according to a certain taxonomic theory, according to which literary works can be divided into four literary genres: poetry, **, script, and prose.

The four-point method is to divide literary works into four categories: **, poetry, script, and prose according to the differences in image shaping, institutional structure, language use, and expression techniques of literary works. Among them, poetry includes lyric poetry and narrative poetry, and prose has a wide range in addition to lyrical prose and narrative prose, such as travelogues, sketches, miscellaneous notes, essays, reportage, etc., all of which fall into this category.

The Seven Strategies were divided into books by the six-point method, but the historiographical classics that later became a large part of the books were only attached to the Spring and Autumn Period of the Seven Strategies and Six Arts Strategies, which also reflected the reality that the number of historical books at that time was small.

The production of the quartile division is a major change in the history of book classification, but the formation of the quartile is not achieved overnight, it is gradually formed on the basis of inheriting and carrying forward the achievements of other classifications, and has its own process of continuous development and improvement, and the quartile method has been used in China for nearly two thousand years, indicating that it has its special significance for sorting out China's ancient books.

Five-point sampling method. It is suitable for investigating the relatively uniform distribution of plant individuals. It is also sometimes used to measure dust particles in the air.

The scope of application of the five-point sampling method: plant population density, insect egg density, aphids, hoppers and other activities of small and weak animal density of activities, rice field yield, etc.

Scope of application of isometric sampling: When the survey population is long, the isometric sampling method can be used. The method of dividing the survey population into several equal parts, determining the distance or interval by the sampling ratio, and then drawing the sample according to the equal distance or interval is called equidistant sampling.

Summary. Wheat quartile sampling refers to dividing a bag of wheat into quarters, weighing and mixing each portion, and then dividing it into three parts for sampling, i.e., a total of 12 parts are sampled. This ensures the adequacy and representativeness of the sampling, and avoids errors caused by uneven sampling.

The specific operation steps are as follows: lay the wheat bag flat on the ground, cut the four corners of the bag with a knife, then cut the mouth of the bag, and then make the bag flat shape. Fold the bag in half, then in half, and then in half, so that it is folded into quarters.

Each equal part of wheat is weighed and mixed, and then divided into three parts, each part is sampled and packed into a bag, and the sampling location, time, quantity, variety and other information are marked to facilitate subsequent inspection and recording. During sampling, care needs to be taken to maintain hygiene and safety to avoid contamination and damage to the wheat. The sampling error can be effectively reduced, the accuracy and reliability of wheat quality detection can be improved, and the food safety and quality of agricultural products can be improved by the quartile method for three times.

Wheat quartile sampling refers to dividing a bag of wheat into quarters, weighing and mixing each portion, and then dividing it into three parts for sampling, i.e., a total of 12 parts are sampled. In this way, the adequacy and representativeness of the samples can be ensured, and the errors caused by uneven sampling can be avoided. The specific steps are as follows:

Place the wheat bag flat on the ground, use a knife to cut the corners of the bag, cut the mouth of the bag, and then make the bag flat shape. Fold the bag in half, then in half, and then in half, so that it is folded into quarters. Each equal part of wheat is weighed and mixed, and then divided into three parts, each part is sampled and packed into a bag, and the sampling location, time, quantity, variety and other information are marked to facilitate subsequent inspection and recording.

During sampling, care needs to be taken to maintain hygiene and safety to avoid contamination and damage to the wheat. The three-time sampling method can effectively reduce the sampling error, improve the accuracy and reliability of wheat quality detection, and help ensure food safety and improve the quality of agricultural products.

Is it like this?

Place the wheat bag flat on the ground, use a knife to cut the four corners of the bag, then cut the mouth of the bag, and then cover the bag to make it flat. Fold the bag in half, then in half, and then in half, so that it is folded into quarters. Each equal part of wheat is weighed and mixed, and then divided into three parts, each part is taken and the sample is packed into a bag, and the sampling location, time, quantity, variety and other information are marked to facilitate subsequent inspection and recording.

Quadrangle sampling, each sample is piled into a uniform cone, and pressed into a cone, and then divided into quarters with a cross-shaped frame.