[R] how to get this kind of binomial distribution simulation number?

[luan_sheng]

hai, I want to perform a simulation like this£º

Suppose that I have one population  ,it's size is 500, is composed of x,y
and z.  The probability of x, y and z is respectively is 0.3, 0.5, 0.2. I
wan to simulate a new same size population based ratio of x, y and z, how
can I get and assess  the number of x, y and z. ?

luan

Key Laboratory for Sustainable Utilization of Marine Fisheries Resources,
Ministry of Agriculture ,Yellow Sea Fisheries Research Institute, Chinese
Academy of Fishery Sciences, Qingdao 266071,China

__________________________________________________

ÑÅ»¢Ãâ·ÑGÓÊÏä£­ÖÐ¹úµÚÒ»¾øÎÞÀ¬»øÓÊ¼þÉ§ÈÅ³¬´óÓÊÏä