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Relations & Functions 101
Represent Date Using Function Models

Representing Data using Function Models

How To: Create a Scatter Plot and find the equation of the line of best fit
 
There are many steps to figuring out how to do this. But after you get the hang of it, it's no problem..
 
To enter data into the calculator   STAT 1
If there us abt date in the list you can clear it by, STAT 4 (Clearlist) L1, 2nd, L2
and continue for the other lists if they contain data. If you cannot see L1 and L2 press STAT 5 ENTER
 
Enter data into L1 and data into L2
 
To create a scatterplot- press 2nd y= ENTER
Turn Plot 1 ON
For Type: highlight the first
X List: L1
Y List: L2
Mark: First
 
ZOOM 9  *this sets the window for scatterplot
 
To view scatterplot: press GRAPH
To create equation: STAT CALC 4 L1, L2 ENTER
 
We see LinReg
            y=ax+b          (a is slope, b is the y-intercept)
To paste equation:
Press y=    Clear any equations that may be there. Then press
VARS 5 > > ENTER
 
This pastes the equation to the y= screen. To see graph press GRAPH
 
*Don't press zoom 7 or 6 since we already set the window for the scatterplot by using zoom 9
 
 
**Now try a couple of your own..
 
SCATTER PLOT #1
X: 1  2  4  5  8  8  10
Y: 2  2  3  5  6  8  10
 
SCATTER PLOT #2
X: 0  1  2  3     5  6  6
Y: 0  2  4  6.5  8  9  10
 

ANSWERS:
 
scatter plot #1
L1   L2
2     2
4     3
5     5
8     6
8     8
10   10
 
2nd y= ENTER
Plot 1 ON
highlight first
x list: l1
y list: l2
mark: first
ZOOM 9
GRAPH
 
STAT CALC 4 L1 , L2 ENTER
 
LinReg
y=ax+b
 
y=
VARS 5 > > ENTER
 
ANSWER: .88X + .37
 
scatter plot #2
 
L1  L2
0    0
1    2
2    4
3    6.5
5    8
6    9
6    10
 
2nd y= Enter
Plot 1 ON
highlight first
X List: L1
Y List: L2
Mark: first
ZOOM 9
GRAPH
 
STAT CALC 4 L1, L2 ENTER
 
LinReg
y=ax+b
 
y=
VARS 5 > > ENTER
 
ANSWER: 1.52X + .66
 
 
 

How to: Read and Interpret Data from a Graph
(Look at the following graph and Explain what is each point means, or what is going on at the time)
 
 
ex. Explain this route a child has taken to get to his buddy's house from home
 
 

realgraph1.gif

Answer:
 
point 1 to point 2: he is going constant for 30 minutes at 80 km.
 
point 2-3: His speed slows down in the next 15 minutes from 80 km to 40 km.
 
point 3-4: His speed gradually goes up from 40km to 60km in the next 15 minutes,
 
point 4-5: He then keeps a constant speed at 60km until he reaches his destination.

How To: Create a Graph to Match a Scenario
 
Look at the following graphs and see which graph best matches this scenario
 
ex.. a bus of kids riding constantly down the highway then reaching a hill, going down it pretty fast then stopping.

Graph A
buss1.gif

Graph B
buss2.gif

Graph C
buss3.gif

Graph D
buss4.gif

Answer: the correct graph is Graph D
 
-Graph A is going all over the place, it doesn't go straight and slow down like it should.  
-It isn't Graph B because it slows down but doesn't stop in the right place.
-It isn't Graph C because it slows down but then speeds up
-It IS Graph D because it gradually slows down and stops

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