120A HW 2
6 :
(a), the sample space is
{
1g,1f,1s,0g,0f,0s
}
, ie, that is there are 6 possible outcomes.
(b),
A
=the event that patient is in serious condition=
{
1s,0s
}
.
(c),
B
=the event that patient is uninsured=
{
0g,0f,0s
}
.
(d),
B
c
=
{
1g,1f,1s
}
, so
B
c
S
A
=
{
1s,1g,1f,0s
}
.
11 : a good way to solve this problem is using Vein diagram.
(a), Percentage of males smokes neither cigars nor cigarettes=1-(28%+7%-5%)=70%.
explanation: (28%+7%-5%) is the percentage of males smokes either cigars or cigarettes.
(b), Percentage of males smokes cigars but not cigarettes=7%-5%=2%.
explanation: by subtracting 5%, we exclude people smoke both cigars and cigarettes from the
group of people who smoke cigars.
28 : without replacement, total number of possible choices is
(
5+6+8
3
)
=
(
19
3
)
;
(a), number of interesting choices (3 balls are of the same color) is
(
5
3
)
+
(
6
3
)
+
(
8
3
)
by using
addition rule. So the probability=
(
5
3
)
+
(
6
3
)
+
(
8
3
)
(
19
3
)
= 0
.
08875129;
(b), number of interesting choices is