2008-I-14

$\begin{array}{cl}=& {\displaystyle \frac{9}{15}}\\ =& {\displaystyle \frac{3}{5}}\end{array}$

1. 所求的概率

   $\begin{array}{cl}=& {\displaystyle \frac{8}{36}}\times {\displaystyle \frac{15}{35}}+{\displaystyle \frac{15}{36}}\times {\displaystyle \frac{8}{35}}\\ =& {\displaystyle \frac{4}{21}}\end{array}$

2. 所求的概率

   $\begin{array}{cl}=& 1–{\displaystyle \frac{8}{36}}\times {\displaystyle \frac{7}{35}}–{\displaystyle \frac{15}{36}}\times {\displaystyle \frac{14}{36}}–{\displaystyle \frac{13}{36}}\times {\displaystyle \frac{12}{35}}\\ =& {\displaystyle \frac{419}{630}}\end{array}$

$\begin{array}{cl}=& {\displaystyle \frac{5000+5000}{2}}\\ =& \mathrm{\$}5000\end{array}$

下四分位數

$\begin{array}{cl}=& {\displaystyle \frac{4300+4300}{2}}\\ =& \mathrm{\$}4300\end{array}$

上四分位數

$\begin{array}{cl}=& {\displaystyle \frac{6400+6400}{2}}\\ =& \mathrm{\$}6400\end{array}$

所以，四分位數間距

$\begin{array}{cl}=& 6400–4300\\ =& \mathrm{\$}2100\end{array}$