What is the standard deviation of 83 82 81 79 78 77?

Calculation Skills (1): Benchmark Number Method.

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Mathematics is a very important subject for students, it has very high requirements for computing ability, and mastering some calculation skills can improve the speed and accuracy of calculations, make complex calculations simple, and thus improve students' academic performance.

Below, I will share with you some calculation skills, hoping to help children learn math well.

1) Benchmark number method. When there are more than two additions, and they are very close, one number can be taken as the base number to calculate.

Example 1: Calculate 47+49+52+53+55

Solution: We can choose the benchmark number as 50, and these five numbers are 3 less than 50, 1 less, 2 more, 3 more, and 5 more, and subtract the less number 4 from the more number 10, and there is 6 left, so we can get:

Example 2: Calculate 32+33+29+30+35

Solution: For the convenience of calculation, the benchmark number can be taken as 30. The sum of the difference between these five numbers and the benchmark number is 9, so that we can get:

Example 3, there are 20 baskets of rice that need to be stored, and the number of catties of rice in each basket is:

What is the total number of catties of rice in this batch?

Solution: The number of catties of each basket of rice is about 80 catties, and 80 is used as the benchmark number, then the total number of this batch of rice is.

1606 (jin) Qiu Chong.

The average is 80

The difference from the mean is 3,2,1,-1,-2,-3 squared and then 9,4,1,1,4,9

The standard deviation is

The mean of the six numbers 83, 82, 81, 79, 78, 77 is 80, so the variance = [(83-80) 2+(82-80) 2+(81-80) 2+(79-80) 2+(78-80) 2+(77-80) 2] 6

The standard deviation is the arithmetic square root of the variance, and the standard deviation of this set of numbers is the arithmetic square root of 14 3, which is approximate.

Solution: s =1 6 [(80-77) +80-78) +80-79) +80-81) +80-82) +80-83)].

Standard deviation. For: s = root number 42 3.

Standard deviation is the arithmetic mean of the square of the mean deviation.

i.e., variance).

Denoted by . Standard deviation is also known as standard deviation.

or experimental standard deviation, which is most commonly used in probability statistics as a basis for measuring the degree of statistical distribution.

The standard deviation is the arithmetic square root of the variance. Standard deviation is a reflection of how discrete a dataset is.

The standard deviation of two sets of data with the same mean is not necessarily the same.

Dispersion: Standard deviation is the most commonly used form of quantification to reflect the dispersion of a pure set of data, and it is an expression of accuracy.

important metrics. When it comes to standard deviation, we must first understand the purpose for which it appears.

We use methods to detect it, but there are always errors in the detection methods, so the detected value is not its true value. The difference between the detected value and the true value is the most decisive indicator for evaluating the detection method.

But what the true value is, it is not known. Therefore, how to quantify the accuracy of the detection method has become a problem. This is also the purpose of quality control in clinical work: to ensure the accuracy and reliability of the results of each batch of experiments.

Although it is impossible to know the true value of a sample, there will always be a true value for each sample, no matter how much it is. It is conceivable that the detection values of a good detection method should be closely dispersed around the true values.

If it is not close, the distance from the true value of the answer will be large, and the accuracy will of course be not good, and it is impossible to imagine that a method with a large dispersion will measure an accurate result. Therefore, dispersion is the most important and basic indicator of the quality of the evaluation method.

Averagex pull=80+(1+2+3-1-2-3) 6=80.

Variance s Fang Jingqiao = [(81-80) 2+(82-80) 2+(83-80) 2+(79-80) 2+(78-80) 2+(77-80) 2] 6=(1+4+9+1+4+9) 6=28 6=14 3.

AverageThe average is the sum of all the data in a set of data, divided by the number of data. An average is the amount that represents the trend in a set of datasets, and it is a metric that reflects the trend in a set of datasets.

The key to solving the average problem is to determine the "total quantity" and the total number of copies corresponding to the total quantity. In statistical work, the average (mean) and the early accuracy of the bidder.

It is a good description of the trend and dispersion of the data in the data.

The two most important measure values.

The average is 80

The difference from the mean is 3,2,1,-1,-2,-3 squared and then 9,4,1,1,4,9

The standard deviation is

Mean = (81 + 82 + 83 + 79 + 78 + 77) 6 = 80

Variance = ((81-80) +82-80) +83-80) +79-80) +78-80) +77-80) )6=(1+4+9+1+4+9) 6=14 3

Standard deviation = variance open arithmetic square root = (14 3) = 52 3

Because of the average. Be.

The variance is. So standard deviation. For.

The standard deviation of the above numbers is 1. This is because such numbers can be arranged in a series of three equal differences. The differences are: 78-77=79-78=1, 81-79=2, 82-81=83-82=1

Standard deviation = (1 2 + 2 1 + 3 1) 5 = (2 + 3 + 3) 5 = 8 5=

A: Their standard deviation is .

The difference is 1 in order, so it should be.