请教大家rpart函数的输出元素都是什么意思呢？非常感谢哦

【原始数据】  

    Play  Outlook TemperatureHumidity  Wind

1  yes    rainy        cool  normal FALSE

2   no    rainy        cool  normal  TRUE

3  yes overcast         hot     high FALSE

4   no    sunny        mild    high FALSE

5  yes    rainy        cool  normal FALSE

6  yes    sunny        cool  normal FALSE

7  yes    rainy        cool  normal FALSE

8  yes    sunny         hot  normal FALSE

9  yes overcast        mild     high TRUE

10  no    sunny        mild    high  TRUE

【命令】

fit <- rpart(Play ~ Outlook + Temperature + Humidity + Wind, method="class", data=play_decision,

    control=rpart.control(minsplit=1),parms=list(split='information'))

summary(fit)

【输出】-----想请教大家下面这些标记的元素都代表什么意思呢？

n=10

        CP nsplit rel error xerror     xstd

1 0.3333333      0        1      1 0.4830459

2 0.0100000      3        0      1 0.4830459

Node number 1: 10 observations,    complexity param=0.3333333

predicted class=yes  expectedloss=0.3

   class counts:     3     7

  probabilities: 0.300 0.700

left son=2 (3 obs) right son=3 (7 obs)

  Primary splits:

    Temperature splitsas  RRL,     improve=1.3282860, (0 missing)

     Wind        < 0.5 to the right,improve=1.3282860, (0 missing)

     Outlook     splits as  RLL,    improve=0.8161371, (0 missing)

     Humidity    splits as  LR,     improve=0.6326870, (0 missing)

  Surrogate splits:

     Humidity splits as  LR,      agree=0.9, adj=0.667, (0 split)

     Wind     < 0.5 to the right,agree=0.8, adj=0.333, (0 split)

Node number 2: 3 observations,    complexity param=0.3333333

predicted class=no   expectedloss=0.3333333

   class counts:     2     1

  probabilities: 0.667 0.333

left son=4 (2 obs) right son=5 (1 obs)

Primary splits:

     Outlook splits as  R-L,     improve=1.9095430, (0 missing)

     Wind    < 0.5 to the left,  improve=0.5232481, (0 missing)

Node number 3: 7 observations,    complexity param=0.3333333

predicted class=yes  expectedloss=0.1428571

   class counts:     1     6

  probabilities: 0.143 0.857

left son=6 (1 obs) right son=7 (6 obs)

Primary splits:

     Wind        < 0.5 to the right,improve=2.8708140, (0 missing)

     Outlook     splits as  RLR,    improve=0.6214736, (0 missing)

     Temperature splits as  LR-,     improve=0.3688021, (0 missing)

     Humidity    splits as  RL,     improve=0.1674470, (0 missing)

Node number 4: 2 observations

predicted class=no   expectedloss=0

   class counts:     2     0

  probabilities: 1.000 0.000

Node number 5: 1 observations

predicted class=yes  expectedloss=0

   class counts:     0     1

  probabilities: 0.000 1.000

Node number 6: 1 observations

predicted class=no   expectedloss=0

   class counts:     1     0

  probabilities: 1.000 0.000

Node number 7: 6 observations

predicted class=yes  expectedloss=0

   class counts:     0     6

  probabilities: 0.000 1.000

【结果图】