Jelaskan sarta keur varian mibanda dari Kamandirian statistik dalam bahasa sunda

var(X + Y) = var(X) + var(Y).

Lamun X jeung Y bébas, kovarian cov(X,Y) sarua jeung nol; dina hal séjén mibanda

var(X + Y) = var(X) + var(Y) + 2 cov(X, Y).

(Pernyataan sabalikna yén lamun dua variabel bébas mangka kovarian-na sarua jeung nol mangrupa hal nu teu bener. Tempo taya hubungan.)

Furthermore, if X and Y are independent and have probability densities fX(x) and fY(y), then the combined random variable (X,Y) has a joint density

fXY(x,y) dx dy = fX(x) fY(y) dx dy.