1. Using the TI84 Graphing Calculator
Data Analysis
Using the TI84 Graphing Calculator
Data Analysis
Using the TI84 Graphing Calculator
Section 0.1

2. Unit Objectives:
To learn the five steps involved in the Data Analysis process.
To become more familiar using the TI84 graphing calculator.
Unit Objectives:
To learn the five steps involved in the Data Analysis process.
To become more familiar using the TI84 graphing calculator.

3. 5 Steps to Data Analysis:
• Create an event
• Look up existing data
Collect the data
Organize the data
Display the data
Regression model
Make predictions
• Table
• List
• Graph
• Chart
5 Steps to Data Analysis:
Collect the data
Organize the data
Display the data
Regression model
Make predictions
• Equation of
best fit
• Use the model to
determine past and
future events.

4. I. Collecting the Data:
You will identify an independent and dependent variable.
Examples:
independent variable:
x-coordinate, input, domain
dependent variable:
y-coordinate, output, range
I. Collecting the Data:
You will identify an independent and dependent variable.
Examples:
independent variable:
x-coordinate, input, domain
dependent variable:
y-coordinate, output, range

5. II. Organize the Data
The independent (x) and dependent (y) values will be placed into a list, chart or table.
(You will be entering the values for
x and y into your graphing calculators)
II. Organize the Data
The independent (x) and dependent (y) values will be placed into a list, chart or table.
(You will be entering the values for
x and y into your graphing calculators)

6. Calculator steps for entering data into a list:
Use the following data:
Number of
Students Time in sec.
Calculator steps for entering data into a list:
Use the following data:
Number of
Students Time in sec.

7. Calculator steps cont…
STAT 1
ENTER
If there is data in your lists, use the arrow keys to move
the curser until the list title (L1) is highlighted. Then
Use the keys on your calculator.
CLEAR
ENTER
Calculator steps cont
Type in your x values one at a time using the
key after each entry to insert it into the list.
Repeat this step to enter your y values.
ENTER

8. III. Graphing the Data: 1. Turn on your plotter
2. Use the ZOOM function to automatically adjust the viewing screen to fit your data.
III. Graphing the Data:
1. Turn on your plotter
2. Use the ZOOM function to automatically adjust the viewing screen to fit your data.

9. Calculator steps for graphing data:
To turn on the plotter:
2nd y=
Enter the number of the plotter you want to turn on.
Today we will turn on Plot2 so you will enter 2

10. Enter each of the following settings and press to go on to the next.
graphing continued…
Enter each of the following settings
and press to go on to the next.
ENTER

11. graphing continued…
ZOOM 9

12. graphing continued…
The graph will now appear in the window. Your x and y axis may not be visible. Remember, the window has been adjusted to fit only the data you entered.

13. IV. Create a Regression Model
Linear equation: straight lines
1. y = kx (parent function)
The graph is a line
The regression model is y=ax+b 1
when k is
positive
when k is
negative

14. Regression Model cont…
Quadratic equation: forms a curve.
2. y = kx2 (parent function)
The graph is a parabola
The regression model is y=ax2+bx+c
when k is
positive
when k is
negative

15. Regression Model cont…
3. y = kx3 (parent function)
The graph is a cubic curve
The regression model is:
y=ax3+bx2+cx+d
when k is
positive
when k is
negative

16. Regression Model cont…
4. y = k√x (parent function)
The graph is a square root
The regression model is:
y=axb (b=.5)
when k is
positive
when k is
negative

17. Regression Model cont…
5. y = k(b)x (parent function)
The graph is exponential
The regression model is:
y=a*bx
when k is
positive
when k is
negative

18. Calculator steps to finding a regression model:
Input:
STAT
Move curser over to
CALC
Calculator display:
4: LinReg
5: QuadReg
6: CubicReg 7: 8: 9:
0: ExpReg
A: PwrReg
Choose the option
based on the shape
of your graph.

19. Calculator steps to finding a regression model:
Since your data looked like it was forming a line, we will use option 4, LinReg.
The screen will now display:
LinReg (ax+b)

20. Calculator steps to finding a regression model:
LinReg (ax+b)
2nd 1 ,
2nd 2 ,
Continue with the following
key sequence:
Input the title of the
list where your x
values are stored.
Input the title of the
list where your y
values are stored.
VARS
move curser over to
Y-VARS 1
(Function) 1
(Y1 )
ENTER

21. Calculator steps to finding a regression model:
The equation for the line will be
automatically put into y1 so you can
graph the equation and your calculator will display the following:
LinReg
y=ax+b a= b=
r2= r=
2.208…
.587…
.989..
.994…

22. Calculator steps to finding a regression model:
If you do not have r2 and r you need to turn on your "diagnostic" as follows:
CATALOG
This will open the catalog that
Contains all of the commands
Available on the TI84 Plus
2nd
Sroll down until you highlight the
command “DiagnosticOn”. Then press
ENTER
ENTER

23. Calculator steps to finding a regression model:
To display your regression model again you need to enter the following key sequence:
Your screen will display:
2nd
ENTER
LinReg
y=ax+b a= b=
r2= r=
2nd
ENTER
2.208…
ENTER
.587…
.989..
.994…

24. Calculator steps to finding a regression model:
There are 2 variables listed on your screen that are very important and require some explanation.
r =
Correlation coefficient:
(*Only used for Linear relationships*)
Indicates the strength of the
relationship and the direction
(slope of the line), positive or
negative.
The closer r is to 1 or -1,
the better the fit.

25. Calculator steps to finding a regression model:
There are 2 variables listed on your screen that are very important and require some explanation.
r2 =
Coefficient of determination:
Indicates the percentage of data
points that lie on the curve.
(Can be used for all regression models.)

26. Calculator steps to finding a regression model:
To superimpose the regression model over the data,
you should now press the key to see the
“Line of Best Fit”.
GRAPH
Line of Best Fit: The average of the data points.

27. What question is really being asked?
V. Making Predictions:
Now that you have graphed the data and found a regression model, you can use the graph and/or the model to make predictions about past or future events.
Make a prediction: How much time would be needed for 43 students to complete the task?
What question is really being asked?
What is y when x is 43?

28. Calculator sequence for making predictions:
TBL SET
Press:
2nd
WINDOW
The calculator will display:
TBL SET
TblStart =
∆Tbl =
Enter the x-value you want
To jump to on the table. 43
Enter how you want the list to
Increment, by 1’s, 2’s, 5’s, or
Even by .1, .01, .001, . . .
Since x represents the number
of students, we won’t need any
decimals so we will make this: 1

29. Calculator sequence for making predictions
Go to the table to get your answer:
TABLE
Press:
2nd
GRAPH
The calculator will display:
95.544
97.753
Use the arrows to scroll up and down if you want
other information, or return to the Table Set.

30. Now, you try: Your Data: Use the given data and the steps of
Data Analysis to:
Graph the data
Create a regression model.
(include values for r and r2)
3. Determine the value of y when x is 53.

31. You try: Practice Problem y-axis x-axis 2 10 14 4 6 8 12 16 18 20 2224 26 28 30 40 50 60 70 80
You try:
x-axis

32. 2. Regression Model: y = 3.268x – 4.439 r = .965 r2 = .931
You try:
2. Regression Model:
y = 3.268x – 4.439
r = .965
r2 = .931
3. Make a prediction:
If x = 53, then y =