Program Pascal Terapan Statistika

program mean;
uses wincrt;
var i,n:integer;
    x, sigma_x, x_bar:real;
begin
write ('banyaknya data= ');
readln (n);
       for i:=1 to n do
       begin
       write ('data ke-', i, '=');
       readln (x);
       sigma_x:= sigma_x+x;
       end;
 writeln ('sigma_x data= ',sigma_x);
 x_bar:= sigma_x/n;
 writeln ('mean data= ', x_bar);
 end.

program varians;
uses wincrt;
var i,n:integer;
    x,sigma_x,sigma_x2,s2:real;
begin
write ('banyaknya data= ');
readln (n);
for i:=1 to n do
  begin
  write ('data ke-',i,' = ');
  readln (x);
  sigma_x:=sigma_x+x;
  sigma_x2:=sigma_x2+sqr(x);
  end;
writeln('sigma_x data= ',sigma_x);
writeln('sigma_x2 data= ',sigma_x2);
s2:=(sigma_x2-(sqr(sigma_x)/n))/(n-1);
writeln ('varians data= ', s2);
end.

program standard_deviasi;
uses wincrt;
var i,n:integer;
    x,sigma_x,sigma_x2,s:real;
begin
write ('banyaknya data= ');
readln (n);
for i:=1 to n do
  begin
  write ('data ke-',i,' = ');
  readln (x);
  sigma_x:=sigma_x+x;
  sigma_x2:=sigma_x2+sqr(x);
  end;
writeln('sigma_x data= ',sigma_x);
writeln('sigma_x2 data= ',sigma_x2);
s:=sqrt((sigma_x2-(sqr(sigma_x)/n))/(n-1));
writeln ('standard deviasi data= ',s);
end.