2. The advantage of 2.mode is that it is less affected by extreme data. The disadvantage of planting trees is that they are unstable, easily influenced by grouping and sample changes, and unable to do further algebraic operations. Mostly used for a group of data with different quality or extreme data. Usage patterns represent typical situations.
3. Median, number, symbol,
4. The advantage of median is that it is not influenced by extreme data and fuzzy data, but the disadvantage is that it can't do further algebraic operation and lacks sensitivity. It is often used to describe the concentration trend of a group of data when it is necessary to quickly estimate the snack level of a group of data, or when there are extreme data or fuzzy data at both ends of a group of data.
5. Four operational properties of arithmetic mean: 1. The total deviation between the original data and its arithmetic mean is 0,2. After each original data is added with the same constant c, the average value of the new data and the average value of the original data are added with this constant c, 3. After each original data is multiplied by the same non-zero constant c, the average value of the new data is the average value of the original data. Multiply this constant c, 4, and each original data is linearly transformed and summed.
6. Method for calculating arithmetic average and method for calculating weighted average,
7. The advantages of average value are strict judgment, sensitive response, conciseness, simple calculation and further algebraic operation.
8. The lack of average value is easily influenced by extreme data and fuzzy data.
9. The use of the average, the first data is homogeneous, the second data is accurate and reliable, and the third needs to get a relatively accurate and reliable concentration, or further participate in other operations.
10. The relationship between the median and the mean of modes shows that the mean of positive skewness is the largest and the mean of negative skewness is the smallest. On which side of the X axis is the flat tail of the curve?
1 1. Full range, also known as extreme range, refers to the difference between the maximum value and the minimum value in a set of data, which is represented by the symbol R.
12. The meaning and calculation formula of percentile. The difference between percentiles refers to the difference between two percentiles and the meaning of quartile and quartile deviation.
13. Average difference, average of the absolute value of your difference, symbol AD, formula,
14. Variance refers to the average, sign and formula of the square of deviation of a set of data.
15. The standard deviation is the square root of variance, which is represented by the symbol S. The original data and the data in the frequency distribution table use different formulas.
16. Advantages of standard deviation, 1, rigorous calculation, a set of data has only one definite standard deviation, 2, sensitive response, 3, suitable for algebraic operation,
17. Lack of standard deviation is easily influenced by extreme data and fuzzy data.