What is the mean plus minus standard deviation In a group of mathematical statistics, it is found that a parameter is not well understood, that is, the mean ± standard deviation of a group of numbers What is the meaning of this in mathematical statistics? My statistics are as follows: The first group of data: (24 25 26) mean: A for standard deviation, B for standard deviation Then I calculate a with a fixed formula to get a value a But later, the software uses a + B to get a + through the above formula, and A-B gets a - What is the significance of this in mathematical statistics?

What is the mean plus minus standard deviation In a group of mathematical statistics, it is found that a parameter is not well understood, that is, the mean ± standard deviation of a group of numbers What is the meaning of this in mathematical statistics? My statistics are as follows: The first group of data: (24 25 26) mean: A for standard deviation, B for standard deviation Then I calculate a with a fixed formula to get a value a But later, the software uses a + B to get a + through the above formula, and A-B gets a - What is the significance of this in mathematical statistics?

The standard deviation of the average is relative to the standard deviation of a single measurement, which is used as the standard to describe the dispersion degree in the normal distribution curve of random error
Under certain measurement conditions (the true value is unknown), if multiple groups of measurements (n times in each group) are carried out for the same measured geometric quantity, there is an arithmetic mean value for each group of N measurements, and the arithmetic mean values of each group are different, According to the error theory, there is a relationship between the standard deviation of the arithmetic mean value of the measurement column and the standard deviation of the single measurement value of the measurement column
σχ=σ /√n
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Standard deviation of single measurement: (calculated by Bessel formula) see the picture
The residual error ν I is the difference between the measured value and the arithmetic mean value
N: Number of measurements