pengendalian mutu statistika

# Input Data
Duplex <- c(408,404,396,397,403,399,396,405,396,404,402,397,398,399,396,402,396,401,400,401,392,408,397,400,414,399,401,400,404,401,402,404,400,404,401,401,400,411,398,404,400,405,407,404,401,400,394,401,402,390)
# Hitung rata-rata
mean(Duplex)

## [1] 400.9

# Membentuk tabel frekuensi
n <- length(Duplex)
range <- max(Duplex)-min(Duplex)
sturgess <- 1+3.3*log10(n)
kelas <- round(sturgess)
breaks <- seq(389, 417, length.out = kelas)
as.data.frame(table(cut(Duplex, breaks = breaks )))

##        Var1 Freq
## 1 (389,394]    2
## 2 (394,398]   11
## 3 (398,403]   23
## 4 (403,408]   10
## 5 (408,412]    3
## 6 (412,417]    1

# Menggambar histogram
hist (Duplex, breaks = breaks)