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The chemical equation of the symbolic expression of the reaction equation of copper heated in air
Reaction formula: Copper + oxygen → copper oxide (heating is written on the arrow)
Symbol expression: Cu + O2 → CuO (heating is written on the arrow)
Chemical equation: 2Cu + O2 = heating = 2CuO
What is the formula for finding the maximum and minimum in mathematics?
Is it B / - 2A and (4ac-b ~) / 4A ("" for square)
When b2-4ac is greater than or equal to zero in y = AX2 + BX + C
If A0, there is a minimum value when x = - B / 2A
The formula of getting the average of the maximum and minimum value out of Excel
Just use the triangle function, use the maximum function, minimum function and sum function to calculate, and then remove the number of data. It's troublesome to input. I think it's too time-consuming
The usage of the function is as follows:
TRIMMEAN(array,percent)
Returns the internal average value of the data set. The trimmean function first removes a certain percentage of data points from the head and tail of the data set, and then calculates the average value. You can use this function when you want to eliminate some data calculations in the analysis
Array is the array or numerical area that needs to be sorted and averaged
Percentage is the proportion of data points to be removed during calculation. For example, if percentage = 0.1, in the set of 20 data points, 2 data points (20 x 0.1) should be removed: one at the head and one at the tail
explain
If percent < 0 or percent > 1, the function trimmean returns the error value # num
The function trimmean rounds down the number of data points to the nearest multiple of 2. If percent = 0.1, 10% of 30 data points is equal to 3 data points. The function trimmean symmetrically removes one data point at the head and one data point at the tail of the dataset
What is the frequency? What is the frequency?
Frequency, also known as "frequency", groups the total data according to a certain standard, and counts the number of individuals in each group. Frequency is the ratio of the frequency of each group to the total number of data. In the variable allocation sequence, frequency (frequency) indicates the degree of action of the corresponding group flag value
Know frequency, how to calculate frequency
Frequency = frequency / total, so frequency = frequency * total
Frequency and the concept of frequency
Frequency: in statistics, a sample is divided into several groups according to a certain method
Frequency: the ratio of the frequency of a group to the sample size is called the frequency of the group. With the frequency (or frequency), we can know the distribution of the number
Mathematical frequency and frequency
If in the frequency distribution histogram of a group of data, the height of a small rectangle is just the sum of the heights of the other small rectangles, then the frequency of the small rectangle group is?
If the group spacing is constant, it is 50%
Frequency histogram
Frequency / total = frequency. Frequency is the number of occurrences of this number
How to calculate the frequency of frequency distribution histogram in Mathematics
How to calculate the frequency of frequency graph in mathematics
Remember two formulas: frequency = area of corresponding small rectangle in histogram = frequency / sample size
The sum of all rectangular areas is 1
Special attention should be paid to the fact that the frequency is not the height of the rectangle. The area obtained by multiplying the height by the group distance is the corresponding frequency of a group
How to calculate the frequency of frequency histogram is the frequency ratio group distance?
Are you talking about the frequency distribution histogram? If it is a frequency distribution histogram, the vertical axis represents the frequency ratio group distance, and the horizontal axis represents the group distance of each group. If you want to find the frequency of a group, multiply the frequency ratio group distance of the vertical axis by the group distance of the horizontal axis to get the group frequency
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