HW Jan 9-16 - WRDSB teachers

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Ouick Review
Data and graphs may be used to make convincing arguments.
Some arguments are more convincing than others.
For example, Lucas and Tia made 2 different arguments using the data in this table.
Amount of Time Spent with Friends after School (to nearest minute)
< 30 min
3G-59
min 6(H9 min 90-l19min >120 min
Tlotal
Girls
6
10
15
t5
4
50
Boys
3
9
t6
t7
5
50
Total
9
r9
3t
32
9
100
Lucas added the data in columns 4 and 5 to find that 22 boys and 19 girls spent more
than 90 min with their friends after school. He used this to argue that boys spend
more time with their friends than girls do.
Tia added the totals of columns 3 and 4 to find that 63 boys and girls spend
60-120 min with their friends after school. She used this to argue that over 600/o of
boys and girls spend l-2h with their friends after school.
Tia's argument is more convincing than Lucas'because only 3 more boys than girls
spend more than 90 min with their friends after school. The numbers are too close
for Lucas'argument to be convincing.
Sometimes, a graph shows a trend or
relationship in the data. When you use data to
predict a value in the future, or to estimate a
value between given data, you make an
inference. When you use data to make
conclusion, you infer.
a
For exarnple, using the data from this graph,
you can make valid arguments and inferences.
Mark High School
Canned Food Drive
St.
Fso40
(r^
oe l0
bE 20
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JO
z
""s
,"$
".o ".s,.t".u$
Year
,..'
The graph shows that, other than 2003, the height of the bar for each year is higher
than the previous year. A convincing argument would be that St. Mark High School
is collecting more cans from year to year.
You can also infer that, if this trend continues, the number of cans collected in 2006
rvill be greater than the number collected in 2005. The prediction, or inference, you
can make is that over 50 000 cans will be collected in 2006.
2. Tawanda recorded in this table the type of cars driven by people in his neighbourhood.
f{
b
Type of Car
Van
SW
Sports Car
Sedan
Number
23
t4
5
9
He used the data in the table to make this argument:
"Most people in my neighbourhood drive A vcln."
a)
Is Tawanda's argument valid? Explain.
Cornpone fhe nurnber
of
vons fo the totol
ndrnber
of
vehicles.
b) Write two convincing arguments that could be justified by the data in the table.
%,,, What
does this graph show?
Students Who Dressed Up
for Spirit Week
100
[!
80
,b
60
z
40
Boys
ffi ci.tt
20
0
Grade
b) Below are 3 arguments made by members of the Student Council.
A: Boys have less school spirit than girls.
B: Grade 8 students have more school spirit than Grade 7 students.
C: Grade 7 students have more school spirit than Grade 8 students.
If there are about the same number of students in each grade, which argument do you
think is most valid? fustily your answer.
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,:tiil&
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102
l.
a) What
does the graph show?
Attendance at Movie Theatre
740
600
500
400
1
fl
ffi
nauts
Youths
-S"os.""t
Day
b) What inferences can you make from the graph? Explain.
Compare the
heights ofthe
bars for adults
and youths
for each
day.
How can the graph be used to justifr each argument?
i) Saturday
is the most popular day for people to go to the movies.
Add the
heights of the
bars for adults
and youths
for each
day.
ii) Approximately equal numbers of adults and youths go the movies on
FridaS Saturday, and Sunday.
@*--*
Add the heights
af the bars for
the 3 days for
adults and
for youths.
101