Answer
mean = 6
standard deviation = 1.12
Work Step by Step
$4, 8, 5, 12, 3, 9, 5, 2$
$4+8+5+12+3+9+5+2 = 48$
$48/8 =6$
$(4-6)^2+(8-6)^2+(5-6)^2+(12-6)^2+(3-6)^2+(9-6)^2+(5-6)^2+(2-6)^2$
$(-2)^2+(2)^2+(-1)^2+(6)^2+(-3)^2+(3)^2+(-1)^2+(-4)^2$
$4+4+1+36+9+9+1+16$
$8+37+18+17$
$45+35$
$80$
$\sqrt {80/8} = 1.12$
