The basic knowledge of statistics

　Let's start!!

Average amount

　The amount you get when you add together several quantities and divide this by the total number of quantities
Example
5 8 3 10 4
This data's average amount is,(5+8+3+10+4)÷5=6.

Median

　The middle number or measurement in a set of numbers or measurements that have been arranged in order
Example
5 8 3 10 4
This data's median is,(3 4 ⑤ 8 10)→5.

Mode

　The Mode value is that the number of that is the most in the number of each data value
Example
7 7 8 8 8
This data's mode is 8.

Deviation

　Assuming that one of the data is x1 and the average amount of the data is x, the deviation is x-x.
　Of course, the average amount of the deviation is 0.
Example
5 8 3 10 4
The deviation of 5 is 6-5=1.

Variance

　The variance is the average of squared the deviation
　This shows how scattering the amount of data　is. If each amount of the data is far from the average, the variance is large amount.
Example
5 8 3 10 4
This data's variance is {(6-5)2+(8-6)2+(6-3)2+(10-6)2+(6-4)2}÷5=6.8.

Standard deviation

　In short, the standard deviation is the square root of variance.
　分散は二乗するため、もしデータの値のそれぞれの単位がｍだったときに分散は㎡になってしまうので平方根を取る。
Example
5 8 3 10 4
This data's standard variance is √6.8=2.6076….