If the laboratory test deviates from the method used, answer 30

The deviation of the inspection and testing method should be good before the omen is judged to have no effect on the results.

Inspection is a scientific term that refers to the working process of using tools, instruments or other analytical methods to check whether various raw materials, semi-finished products and finished products meet specific technical standards and specifications. The inspection is to compare the measurement results with the quality standards through the sub-determination of the lead products (raw materials, semi-finished products, and finished products), and make a judgment on whether they are qualified or not, and whether they can be suitable for the use of the next process or whether they can be provided to the user for processing.

The inspection includes four links: measurement, comparison, judgment and processing. The inspection applies both to individual products and to batches of products; It is suitable for both finished product inspection and process inspection of semi-finished products or finished products.

Introduction:

The examination of physical properties is usually referred to as a physical test; The examination of chemical properties or composition is called a chemical test or simply a laboratory test. There are generally destructive tests and non-destructive tests, the former can only be sampled from the whole for spot checks, and then mathematical statistical methods are used to infer the overall situation; The latter can be examined on a case-by-case basis. Considering the category of the inspected object, people often divide it into semi-finished product inspection, finished product inspection or commodity inspection.

It also refers to the working process of using tools, instruments or other analytical methods to check whether various raw materials, semi-finished products and finished products meet specific technical standards and specifications. This is an activity that is carried out to measure, measure, inspect, and experimentally analyze entities in a product or process, compare the results with the specified values, and determine whether they are qualified.

Answer]: Analysis of the Basis: Article 1 of the "Evaluation Criteria for Laboratory Qualification Accreditation".

The deviation of the detection and calibration method shall be verified by the relevant technical unit or approved by the relevant competent department, approved by the person in charge of the laboratory and accepted by the customer, and the deviation of the method shall be documented.

When there are two or more different results in the trial copy data, statistical methods should be used to determine whether there is a significant difference between the test data through the significance test.

The methods of significance testing are usually t-test and f-test

The t-test is used to test the accuracy of two sets of data to determine whether there is a systematic error.

The f-test, also known as the variance homogeneity test, is used to detect the precision of two or more sets of data to determine whether there is an accidental error.

I won't write about calculation formulas and look-up tables, it's too complicated, and you should have it all in your hands.

For your data, if you just "need to see if the difference between the two groups is very big", just use the f test.

If you need to determine if the data is systematically incorrect, or if it matches a hypothetical conclusion, you need to use the t-test.

As a reminder, if you want to perform the t-test, you must first perform the f-test to determine the sameness of the variance between the two sets of data.

If the variance of the two sets of data is equal, the t-test is used; If the variance is unequal, the t of the variant is used'Inspection.

In any case, the f-test is used.

Answer]: Natural variation.

Analysis: The influence of natural variation and non-treatment factors on the observation results can be excluded by control. Since the learning effect or training effect is not entirely determined by the influence of teaching and training training, it is only by using the comparison that it can be fully clarified whether the observation results belong to the effect of treatment factors or other scattered causes.

What are the factors that affect the error of the measurement results in the three-wire torsion pendulum experiment? The length of the cycloid, the leveling state of the device, the eccentricity distribution in the mass. After the three-line is placed on the DUT, is its rotation period necessarily larger than that of the empty disk?

Why? Answer: However, due to the effect of resistance such as air and other resistance in the process of twisting the three-wire pendulum, it is actually a damping vibration, and the corresponding period of the state tomb beam will become longer.

The error of the measured period is larger. And since I0 T02, the error caused by the measurement period is systematic.

Answer: Analysis:

The error of this experiment is mainly in the following three aspects: The length and thickness of the rubber band are different, so that the tensile force of the rubber band is not proportional to the number of rubber bands; The position where the force of the trolley is 0 is not necessarily at the set point; Because the position of the trolley that is not subject to tension is not necessarily at the set point, this makes the tensile work w not proportional to the number of rubber bands, and the unit length of the ordinate when making the image still takes the value of the work and the number of rubber bands in proportional relationship, so that the distribution of each corresponding point of w and v is deviated from the function image