diff --git a/reference/random/random.png b/reference/random/random.png
index 3cd2ea2..793b83f 100644
Binary files a/reference/random/random.png and b/reference/random/random.png differ
diff --git a/reference/random/random_stats.R b/reference/random/random_stats.R
index 4fec310..05a9459 100644
--- a/reference/random/random_stats.R
+++ b/reference/random/random_stats.R
@@ -11,7 +11,7 @@ value1 = x$V1
 value2 = x$V2
 
 # 折れ線グラフを2つ混ぜて出力
-plot(density(value1), xlim=c(-1,4), ylim=c(0.0,0.8), type="l")
+plot(density(value1), xlim=c(-1,4), ylim=c(0.0,0.8), type="l", lty="longdash", col=rgb(0,1,0))
 par(new=T)
-plot(density(value2), xlim=c(-1,4), ylim=c(0.0,0.8), type="l")
+plot(density(value2), xlim=c(-1,4), ylim=c(0.0,0.8), type="l", col=rgb(0,0,1))