[.13 d] Computer chips often contain surface imperfections. For a certain type of computer chips, the probability mass function of the number of defects. K is presented in the foowing table. .3: [II 1 2 3 4 5 Pix)! [132 [LED 13.15 1116 [1.15 [3.02 Find ETC :1 2}. {4 points: Find Ex s 13.. {4 points] Find the mean number of defects} .\"r;i'1' points} Find the variance of the number of defects} :52 {=1- points]