Решебник по математике 9 класс. вероятность и статистика Высоцкий ФГОС Часть 1 Задание 320

\[\boxed{\mathbf{320.}}\]

\[\textbf{а)}\ \overline{x} = \frac{1 + 3 + 5 + 1 + 3}{5} =\]

\[= \frac{13}{5} = 2,6;\]

\[\overline{x^{2}} = \frac{1 + 9 + 25 + 1 + 9}{5} = 9;\]

\[S^{2} = 9 - {2,6}^{2} = 9 - 6,76 = 2,24.\]

\[S = \sqrt{2,24} = 1,497 \approx 1,5.\]

\[\textbf{б)}\ \overline{x} =\]

\[= \frac{0,2 + 0,4 + 1,1 + 1,4 + 0,7}{5} =\]

\[= \frac{3,8}{5} = 0,76;\]

\[S^{2} = 0,772 - {0,76}^{2} =\]

\[= 0,772 - 0,5776 = 0,194.\]

\[S = \sqrt{0,194} \approx 0,44.\]

\[= \frac{791\ 407}{6} \approx 131\ 901,167.\]

\[S^{2} = 131901,167 - {342,5}^{2} =\]

\[= 14594,92.\]

\[S = \sqrt{14594,92} \approx 120,81.\]

\[S^{2} = 0,439 - {0,51}^{2} = 0,179.\]

\[S = \sqrt{0,179} \approx 0,42.\]