查找R中的数据列的平均值

Question

我正在处理有关暗杀企图的数据。我必须找到领导者生存的国家的平均基线政治得分 那些没有的人。

数据集如下：

"year","country","leadername","age","politybefore","polityafter","interwarbefore","interwarafter","civilwarbefore","civilwarafter","result"

1929,"Afghanistan","Habibullah Ghazi",39,-6,-6,0,0,1,0,"not wounded"

我认为我要做的是创建两个数据子集，一个成功的尝试和一个不成功的尝试，然后找到"politybefore"列的平均值，但我不知道最有效的方法。

结果的选项是：

＆＃13;

＆＃13;

levels(leaders$result)
[1] "dies between a day and a week"              
 [2] "dies between a week and a month"            
 [3] "dies within a day after the attack"         
 [4] "dies, timing unknown"                       
 [5] "hospitalization but no permanent disability"
 [6] "not wounded"                                
 [7] "plot stopped"                               
 [8] "survives but wounded severely"              
 [9] "survives, whether wounded unknown"          
[10] "wounded lightly" 

＆＃13;

＆＃13;

＆＃13;

因此导致死亡的任何事情都是成功的。