p = π/4 与 所得 0.7854 比较接近，故满足 Central Limit theorem。
simulation = function(sampleSize){
c = rep(0,sampleSize)
countIn = 0
for(i in 1:sampleSize){
x = runif(1,-1,1)
y = runif(1,-1,1)
if(sqrt(x*x + y*y) <= 1){
countIn = countIn + 1
}
piHat = countIn / i
c[i] = piHat
}
return(c)
}
pointEstimate = function(testCount){
cc = rep(0,testCount)
for(i in 1:testCount){
sampleSize = 1000
res = simulation(sampleSize)
cc[i] = res[1000]
}
return(cc)
}
testCount = 1000
res = pointEstimate(testCount)
/* 获得很多要构成长条的点 */
hist(res, freq = F, breaks = testCount)
mean(res)