Let $\mathrm{x}_1, \mathrm{x}_2, \mathrm{x}_3, \mathrm{x}_4$ and $\mathrm{x}_5$ be the observations with mean $\mathrm{m}$ and standard deviations. Then, standard deviation of the observations $\mathrm{kx}_1, \mathrm{kx}_2, \mathrm{kx}_3, \mathrm{kx}_4$ and $\mathrm{kx}_5$ is