Questions
2.2.1.
A graduating engineer has signed up for three job interviews. She intends to categorize each one
as being either a “success” or a “failure” depending on whether it leads to a plant trip. Write out the
appropriate sample space. What outcomes are in the event A: Second success occurs on third interview?
In B: First success never occurs?
Solution
Let s be success and f be failure.
S = {sss, ssf, sfs, fss, sff, fsf, ffs, fff}
From the sample space, we can immediately find for the two events. That is,
A =
{sfs, fss}
B =
{fff}
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View Full Document2.2.5
A woman has her purse snatched by two teenagers. She is subsequently shown a police lineup
consisting of five suspects, including the two perpetrators. What is the sample space associated with the
experiment “Woman picks two suspects out of lineup”? Which outcomes are in the event, A, that she
makes at least one incorrect identification?
Solution
Let the three innocents be i
1
, i
2
, and i
3
respectively.
p
1
and
p
2
be the two perpetrators.
The sample space then is S = {( i
1
, i
2
), (i
1
, i
3
), (i
1
,
p
1
), (i
1
,
p
2
), (i
2
, i
3
), (i
2
,
p
1
), (i
2
,
p
2
), (i
3
,
p
1
), (i
3
,
p
2
), (
p
1
,
p
2
)}
Therefore, for us to determine the event A, we need to look on the sample space where
p
1
and
p
2
is
partnered with other number and those numbers where it is not belong since we need at least one
incorrect identification. Thus, the sample outcome of the said event is all the elements in the sample
space except for (
p
1
,
p
2
).
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 Spring '11
 Tomas
 Math, Statistics, Probability

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