6. Randy spends money for dinner according to the following probability chart.

$\displaystyle {x}$	$\displaystyle {P}{\left({x}\right)}$
15	0.16
20	0.19
25	0.15
30	0.5

Dan spends money for dinner according to the following probability chart.

$\displaystyle {x}$	$\displaystyle {P}{\left({x}\right)}$
20	0.2
25	0.28
30	0.12
35	0.4

Round all answers below to 2 decimal places.

a. Find the average amount of money Randy spends.

$

b. Find the standard deviation of the amount of money Randy spends.

$

c. Find the average amount of money Dan spends.

$

d. Find the standard deviation of the amount of money Dan spends.

$

e. Find the average amount of money they spend for dinner together.

$

f. Find the standard deviation of the total money they spend for dinner together.

$

g. Find the average difference in money they spend for dinner. (Randy - Dan)

$

h. Find the average standard deviation of the difference they spend for dinner.

$