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Q
uantitative
R
easoning &
P
roblem
S
olving
64
© 2014 Pacific Crest
O
ops
! A
voiding
C
ommon
E
rrors
●
Not narrowing the search but expanding the characteristics of the intended a set
Example
: Doing an internet search for
Washington
could yield the state, the president, the
scientist, or the city when you wanted to find information about George Washington.
Why?
When performing a search, the fewer the characteristics you use in a query, the more
general the search results will be. To narrow a search and limit the search results,
increase the characteristics used in the query. The more characteristics you use, the
fewer the number of objects there will be that meet all the characteristics.
●
Redundancy in union
—
keeping multiples of the same object
Example
: A union of the sets {3,4,5} and {7,6,5} is not {3,4,5,7,6,5}.
Why?
The cost of storing and keeping track of redundant objects can take up time and
resources.
●
Keeping objects from two sets even though they are not in the intersection
Example
: Webster High School and Local Community College wanted to share data so they
combined their student records where the total set included 1) students going to
Webster, 2) those going to LCC, and 3) those going to both schools.
Why?
The comparing of characteristics that Webster stored with LCC characteristics only
make sense for those students in both institutions (the intersection of sets). Thus the
number of objects should not be the union but the intersection of student records.
A
re You Ready?
Before continuing, you should be able to ...
I can...
OR
Here’s my question...
identify the characteristics and objects of
a specific set
determine, based upon a given object and
its characteristics, if the object belongs in
a specific set
take the union and intersection of two sets
take the complement of a set