3.1 Notes Alg1M.notebook October 22, 2012 3.1 Graphing Relationships Can you think of a situation which these graphs could represent? 3.1 Graphing Relationships 1. Match simple graphs with situations. 2. Graph a relationship. Displaying trends, visually communicating large data
3.1 Notes Alg1M.notebook3.1 Graphing Relationships
Can you think of a situation which these graphs could represent?
3.1 Graphing Relationships
1. Match simple graphs with situations.
2. Graph a relationship.
Displaying trends,
visually communicating large data
3.1 Notes Alg1M.notebook October 22, 2012
I. Relating Graphs to Situations
1. Each day several leaves fall from a tree.
One day a gust of wind blows off many
leaves. Eventually, there are no more
leaves on the tree. Choose the graph that
best represents the situation.
Step 2 List key words in order and decide which graph shows them.
Step 1 Read the graphs from left to right to show time
passing.
Step 3 Pick the graph that shows all the key phrases in order.
2. The air temperature increased steadily for
several hours and then remained constant.
At the end of the day, the temperature
increased slightly before dropping sharply.
Choose the graph that best represents this situation.
What are the key words that led you to choose your graph?
3.1 Notes Alg1M.notebook October 22, 2012
II. Determining Continuous versus Discrete
The graph on theme park
attendance is an example of a
discrete graph. It consists of
distinct points because each
year is distinct and people are
counted in whole numbers only .
The values between whole
numbers are not included, since
they have no meaning for the
situation.
Continuous graph
Discrete graph
As seen in Example 1, some graphs are connected
lines or curves called
continuous graphs.
Some graphs are only distinct points. They are
called discrete graphs.
III. Sketching Graphs for Situations
3. Sketch a graph for the situation.
Tell whether the graph is continuous or discrete.
"A truck driver enters a street, drives at a constant
speed, stops at a light, and then continues."
As time passes during the trip (moving left to
right along the xaxis) the truck's speed (yaxis) does
the following:
The graph is continuous.
Helpful Hint
When sketching or interpreting a graph,
pay close attention to the labels on each
axis!
4. Sketch a graph for the situation. Tell whether
the graph is continuous or discrete.
"A small bookstore sold between 5 and 8 books
each day for 7 days."
b. What is an appropriate range and scale
for each axis?
a. What variable would go on the xaxis? yaxis? Why?
c. Sketch the graph.
d. Is the graph discrete or continuous?
The graph is discrete.
The number of books sold (yaxis)
varies for each day (xaxis).
Since the bookstore can only sell
whole numbers of books, the
graph is 7 distinct points.
3.1 Notes Alg1M.notebook October 22, 2012
5. Jamie is taking an 8week keyboarding class.
At the end of each week, she takes a test to find
the number of words she can type per minute. She
improves each week.
a. What variable is on the x and yaxis?
b. Appropriate range and scale?
c. Sketch graph.
d. Discrete or continuous?
Each week (xaxis) her typing speed is
measured.
She gets a separate score (yaxis) for
each test.
Since each test score is a whole number,
the graph consists of 8 distinct points.
The graph is discrete.
6. Henry begins to drain a water tank by opening a
valve. Then he opens another valve. Then he closes
the first valve. He leaves the second valve open until
the tank is empty.
a. What variable is on the x and yaxis?
b. Appropriate range and scale?
c. Sketch graph.
d. Discrete or continuous?
As time passes while draining the tank
(moving left to right along the xaxis)
the water level (yaxis) does the
following:
• initially declines
• decline more rapidly
• and then the decline slows
down.
The graph is continuous.
IV. Intro to Writing Situations for Graphs
7. Can you think of a situation which these
graphs could represent?
Step 2: Analyze sections. For example...
over time, the speed...
Step 1: Identify labels on x and y axis.
Possible situation:
Both graphs show a relationship about a child going down a slide.
Graph A represents the child’s distance from the ground related to
time.
Graph B represents the child’s Speed related to time.
8. Can you think of a possible
situation which this graph could
represent?
Step 1: Identify labels on xaxis:_____ and yaxis______.
Step 2 Analyze sections... over time, the speed...
Possible situation:
A car approaching traffic slows down, drives at a constant speed, and
then slows down until coming to a complete stop.
3.1 Notes Alg1M.notebook October 22, 2012
9. Can you think of a situation which this graph
could represent?
Step 1: Identify labels on xaxis:_____ and yaxis______.
Step 2 Analyze sections... over time, the speed...
Possible situation:
When the number of students reaches a certain point,
the number of pizzas bought increases.
3.1 p.167 #3 16 all, 22 24, 26 28
*20 problems
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