#1
[tex]\\ \rm\Rrightarrow Mean=\dfrac{10+7.5+7.5+9+12+8}{6}=\dfrac{54}{6}=9[/tex]
#2
[tex]\\ \rm\Rrightarrow Mean=\dfrac{12+12+11.5+11.5+12.5+13}{6}=72.5/6\approx 12[/tex]