box-line plots and four-digit points

Http://blog.sina.com.cn/s/blog_6a706ff30100sgbb.html

What is a four-digit number of points.

The quartile, which is statistically, arranges all the values from small to large and divides them into four equal points, with a score of four in the three-point position.

The 14th Division (Q1), also known as the "smaller four", is equal to the number of all the values in the sample from small to large after the 25th.

The 24th (Q2), also known as the "median", is equal to the number of all values in the sample from small to large after the 50th.

The 34th Division (Q3), also known as the "larger four", equals the number of all values in the sample from small to large after the 75th.

The gap between the 34th and 14th is also known as the four-point distance (Interquartile RANGE,IQR).

The example first determines the location of the four-digit number:

Q1 position = (n+1)/4

Q2 position = (n+1)/2

Q3 's position =3 (n+1)/4

n indicates the number of items

Example 1

Total data: 6, 47, 49, 15, 42, 41, 7, 39, 43, 40, 36

Results arranged from small to large: 6, 7, 15, 36, 39, 40, 41, 42, 43, 47, 49

Altogether 11 items

Position of Q1 = (11+1)/4=3 Q2 location = (11+1)/2=6 Q3 location =3 (11+1)/4=9

Q1 = Q2 = Q3 = 43

Example 2

Total data: 7, 15, 36, 39, 40, 41

Altogether 6 items

Position of Q1 = (6+1)/4=1.75 Q2 location = (6+1)/2=3.5 Q3 location =3 (6+1)/4=5.25

Q1 = 7+ (15-7) x (1.75-1) = 13,

Q2 = 36+ (39-36) x (3.5-3) = 37.5,

Q3 = 40+ (41-40) x (5.25-5) =40.25