\[\boxed{\mathbf{1204}\mathbf{.}}\]
\[1)\ \ 3\ кг;\ 5\ кг;\ 5\ кг;\ 8\ кг;\ 4\ кг;\]
\[\overline{X} = \frac{3 + 5 + 5 + 8 + 4}{5} = \frac{25}{5} = 5.\]
\[= \frac{4 + 9 + 1}{5} = \frac{14}{5} = 2,8.\]
\[\sigma = \sqrt{D} = \sqrt{2,8} \approx 1,67.\]
\[2)\ 12\ м;\ 10\ м;\ 7\ м;\ \ 12\ м;\ 9\ м;\]
\[\overline{X} = \frac{12 + 10 + 7 + 12 + 9}{5} =\]
\[= \frac{50}{5} = 10.\]
\[= \frac{2^{2} + 0^{2} + 3^{2} + 2^{2} + 1^{2}}{5} =\]
\[= \frac{4 + 9 + 4 + 1}{5} = \frac{18}{5} = 3,6.\]
\[\sigma = \sqrt{D} = \sqrt{3,6} \approx 1,89.\]