我有以下代碼如何dbeta的函數被調用R中
#emp bayes
num_trials <- 10e6
simulations <- data_frame(
true_average = rbeta(num_trials, 81, 219),
hits = rbinom(num_trials, 300, true_average)
)
hit_100 <- simulations %>%
filter(hits == 100)
dens <- function(z) dbeta(z, 81 + 100, 219 + 200)
ggplot(hit_100, aes(true_average)) +
geom_histogram(aes(y = ..density..),bins = 100) +
stat_function(color = "red", fun = dens) +
labs(x = "Batting average of players who got 100 H/300 AB")
我理解R的功能和基本知識,如
square.it <- function(x) {
square <- x * x
return(square)
}
# square a number
square.it(5)
## [1] 25
但差異密度函數是z
沒有值輸入行
dens <- function(z) dbeta(z, 81 + 100, 219 + 200)
或線路
stat_function(color = "red", fun = dens)
所以我的問題是,如何爲R能夠創造ggplot光滑函數時提供的密度函數沒有價值?
我猜,因爲只有一個參數'dens()'傳遞正確的對象。 – thelatemail