program Lab5_1;

const lmax = 20;

type mass = array[1..lmax] of real;

var a: mass;
    z : real;
    i, n: integer;

function f (var a : mass; n : integer; var z : real) : real;
var sum, sum1, s: real;
    i: integer;
begin
    sum := 0;
    sum1 := 0;
    for i := 1 to n do
        sum := sum + a[i];
    s := sum / n;
    f := s;
    for i := 1 to n do
        sum1 := sum1 + (a[i] - s) * (a[i] - s);
    z := sqrt(sum1 / n);
end;

begin
    writeln ('Лабораторная работа №5');
    writeln ('1 задание');
    repeat
        writeln ('Введите n>0');
        read (n);
    until (n > 0);

    writeln ('Введите числа до ', n);
    for i := 1 to n do
        read (a[i]);

    writeln ('Ответ:');
    writeln (f(a, n, z));
    writeln (z);
end.