$(25$ points$)[$tracing$]$ What are the values of $x,y,a,b,c,m$ and n after the following script is run?

$x=[1$:$3$:$7]\frac{.}{7\text{:}-3\text{:}1},4$ points;

$y=$ pi$/2$ : pi$/2$ : $2*$pi $4$ points

round $(x)$;$\frac{y}{?}$ mean $(y)$ points

$b=a(1,$:$)-a($end$,,4$ points

length $(x)$ points

$m=$prod$\frac{c}{{\displaystyle \underset{?}{\overset{?}{}}}}(c),3$ points

$n=$max$(min(a)),3$ points