Do Now 12/2/09
Take out HW from last night.
- Punchline worksheet 7.19
Copy HW in planner.
- Text p. 328, #3-6, 8-12 evens, 16 & 17 (4 graphs)
- Quiz sections 5.5 - 5.7 Friday
Homework
Punchline worksheet 7.19
1) y – 2 = 4/3(x – 7)
2) y + 4 = -2/5(x – 4)
3) y = 3x + 8
4) y = 1/4x + 3/2
5) 2x + 3y = -11
6) -5x + y = 7
7) y – 7 = 2(x + 4)
8) y + 1= -3/8(x – 6)
9) y = 5/2x – 1
10) y = -1/6x + 3/2
11) -3x + 4y = 15
12) 7x + 2y = -15
13) y = 5/3x – 3
14) y = -4/9x – 40/9
15) y = -3x – 6
“Did You Hear About the
Mathematician Who Wanted to
Make a Fruit Salad, So He
Bought Some Apples and
Oranges?”
“AND ORDERED PEARS”
Objective
SWBAT make scatter plots and write
equations to model data
Section 5.6 “Fit a Line to Data”
Scatter Plot
a graph used to determine whether there is
a relationship between paired data.
y
x
Scatter plots can show trends (patterns) in
the data.
y
y
x
Positive correlation
As y tends to increase,
x tends to increase.
y
x
x
Negative correlation
Relatively
no correlation
As y tends to decrease,
x tends to increase.
x and y have
no apparent
relationship.
Make a scatter plot of the data in the table.
Describe the correlation of the data.
x
1
1
2
2.5
3
3.5
4
5
y
1
2
2
3
3.5
3
4
4
y-axis
The scatter plot
shows a positive
correlation because
as x tends to
increase, y tends to
increase.
4
3
2
1
0
1
2
3
4
5
6
7
x-axis
Make a scatter plot of the data in the table.
Describe the correlation of the data.
Minutes on
treadmill
0
5
10
15
20
25
30
35
Ounces of
water in
water bottle
12
12
10
9
7
7
5
3
y-axis
The scatter plot
shows a negative
correlation because
as minutes on the
treadmill increase,
ounces of water in
the water bottle
decreases.
12
8
Ounces
of water
in water
bottle
4
0
5
10
15 20 25 30 35
Minutes on the treadmill
x-axis
Modeling Data
When data show a positive or negative
correlation, you can model the trend in the
data using a
LINE OF FIT
Using a Line of Fit to Model Data
1)
2)
3)
4)
.
Make
a scatter plot of the data.
.
Decide
whether the data can be a modeled by a line.
(Does it have positive or negative correlation?)
.Draw a line that appears to fit the data closely.
.Write an equation using two points on the line.
(The points do not have to be actual data pairs, but
they do have to be on the line.)
Draw a line of fit for the scatter plot. Write an equation that
models the number of ounces of water left in the water
bottle as a function of minutes on the treadmill.
Minutes on
treadmill
0
5
10
15
20
25
30
35
Ounces of
water in
water bottle
12
12
10
9
7
7
5
3
Write an equation using two
points on the line.
y-axis
12
Use the points (5,12) and (30,4).
12 – 4 = _8_
5 – 30
-25
8
Ounces
of water
in water
bottle
Find the y-intercept. Use (5,12).
4
y = mx + b
12 = 8 (5) + b
-25
0
5
10
15 20 25 30 35 x-axis
Minutes on the treadmill
y=
8 x + 68
-25
5
b = 68
5
Draw a line of fit for the scatter plot. Write an equation that models the
number of years since 2000 as a function student enrollment.
Years
0
1
2
3
4
5
6
7
8
9
880
890
895
890
900
900
910
905
920
930
since 2000
Enrollment
Enrollment at Howell Middle School South
950
Student enrollment
940
Write an equation using two
points on the line.
Use the points (4, 900) and
(6, 910).
930
910 – 900
6–4
920
= _10_ = 5
2
910
Find the y-intercept.
Use (4, 900).
y = mx + b
900
890
880
900 = 5(4) + b
x-axis
00
01 02
03 04 05 06 07
year
08 09
y = 5x + 880
b = 880
24
Homework
Text p. 328, #3-6, 8-12 evens, 16 & 17
(4 graphs)
0
