On-Line Seminar, Spring 1997

Week 1:
Using Graphing Calculators in Science & Math Classes

A. Basic Operations of the TI-82

1. To turn calculator on: Press [ON]
2. To multiply 3 x 4: Press [3] [x] [4] [ENTER] (notice that the answer appears on the right side of the screen, after you press [ENTER])
3. To turn calculator off: Press [2nd] [OFF]
4. Turn calculator on again. You should see that the calculator remembers (stores in memory) your last action.
5. To clear the screen: Press[CLEAR]. [CLEAR] erases what is on the screen and that info is gone forever!
6. Press [MODE]:
   • We can tell the calculator to record numbers in Normal, Scientific Notation, and Engineering modes. The example above used the normal mode. Arrow over to SCI and press [ENTER] to record the answer to [3] [x] [4] [ENTER] in scientific notation as 1.2E1, which is 1.2 x 101.
   • We can also use this key to change the number of decimal points. Press [MODE]. Arrow down to (Float) to set the decimal place based on the data entered. Arrow to (5) and press [ENTER] to tell the calculator to report the answer to [3] [x] [4] [ENTER] to five decimal places. Set [MODE] to normal and float to 1 decimal before going on to number 7 .
7. Look at the color and writing on and above the keys. Notice that each performs two or three different functions.
   • Press [2nd] [QUIT]. When you press [2nd], it activates the blue [QUIT]. Use these two keys to quit a function. This does not erase them from the calculator, it just quits that operation. Press the [2nd] key, release it, then press the [QUIT] key.
   • The [ALPHA] key activates the gray functions. Press [ALPHA] [H] [ALPHA] [E] [ALPHA] [L][ALPHA] [L] [ALPHA] [O]. Notice the change in the cursor when you press either the [2nd] key or the [ALPHA] key. The cursor changes from a  to an ^ when [2nd] is pressed and A when [ALPHA] is pressed. Pressing [2nd] or [ALPHA] a second time will return you to the normal cursor.

B. Delete a List

1. Press{STAT]. (EDIT) should be highlighted. Press[ENTER]. (If there is data in a list format, continue instructions 2----->5, if there isn't any data, go to "C".)
2. Arrow up and over to the heading(top) of the list that you want to delete.
3. Press [CLEAR] (this command will cause the bottom of the line screen to become "L1= ").
4. Press [ENTER] (this command deletes the entries in the list)
5. Repeat the above operation to delete lists L1 ----> L6

C. Create a List

1. Suppose your assignment is to graph the data (ordered pairs) from the table below: Time Position 0.0 0.0 1.0 5.0 2.0 20.0 3.0 45.0 4.0 80.0 5.0 125.0 6.0 180.0
2. Press [STAT] {TI should be in (Edit Menu) and (Edit) sub menu highlighted in the (STAT EDIT) menu}
3. Press [ENTER] OR Press [1]. (This selects the Edit menu; the first entry under the list L1 should be highlighted.
4. Enter 0.0 for the first time data point. (note that the value you are entering appears on the bottom line)
5. Press [ENTER] (Note that the value now is entered as the first element of list 1 and that the cursor now moves to the second element of the L1 list)
6. Enter the remaining time data.
7. Press [>] (right arrow key; this moves the cursor to the first entry of list L2)
8. Enter the position data. (check to see that both L1 and L2 have the same number of entries)

D. Make Corrections to a List

Press[STAT]. (EDIT) should be highlighted. Press[ENTER]. Use the arrow keys to position the cursor over the entry that you wish to modify; type the new entry and press [ENTER].

E. Graph Two Data Sets

1. Press [2nd] [STATPLOT] (under the Y= key). (this displays the stat plots screen; note that Plots are either turned "ON" or "OFF".)
2. Press [1] OR use the cursor to highlight 1 and Press [ENTER]. (this command displays the Plot1 screen
3. The 5 options to select include:
   • On vs. Off : On indicates that this particular plot information will be activated when [GRAPH] is pressed; to turn On, position cursor over (On) and press [ENTER]. Off indicates that this screen will not be activated when [GRAPH] is pressed.
   • Type: Your choices are scatter plot, line/curve connecting data points, box plot, and histogram.
   • Xlist: This determines which list will be plotted on the X (horizontal axis); to select list L1, use the arrow keys to move the flashing cursor over the desired list and press [ENTER]. (highlighted non-flashing entry is selected)
   • Ylist: This determines which list will be plotted on the Y (vertical axis); to select list L2, use the arrow keys to move the flashing cursor over the desired list and press [ENTER]. (highlighted non-flashing entry is selected)
   • Mark: This determines the shape/size of the data points plotted.
4. After selecting the desired options, (remember to turn the plot ON!), press [GRAPH].
5. Your graph may not display all of your data points because the graphing window is not yet set properly. Press [ZOOM] [9] to automatically select a window that displays the full range of your data.
6. To manually set your own window, press {WINDOW] and enter the desired settings.
7. Plots of different lists can be graphed simultaneously using Plot 2 and Plot 3. All of the plots that are turned on will be displayed when you press [GRAPH].

F. Re-expressing Lists

Press [GRAPH]. Notice that the relationship between the L2 and L1 data is not linear....The purpose of this section is to re-express one or both of the lists so that a linear relationship exists between them.

To plot L2 vs. (L1)2

1. Press [STAT].
2. Press[ENTER] in order to Edit.
3. Arrow the cursor over/up to highlight (L3). (notice that (L3= ) appears at the bottom of the screen)
4. Press [2nd] [L1]. (the bottom line now reads L3 = L1)
5. Press [X2]. (the bottom line now reads L3 = L12)
6. Press [ENTER]. (the entries under L3 should be the squares of the entries under L1: check to see!)

graphing the re-expressed lists:

We'd like to see if the relationship between L2 and the re-expressed data in L3 is linear....What do you do now to produce this new plot? Is it possible to tell if the relationship between L2 (position) and L3 (time squared) is linear?

Homework: What if the relationship between our original data (position in L2 and time in L1) is linearly proportional to t4? Create a list of t4 values and store in L4; then graph position data (in L2) vs. t4 data (in L4); Is the relationship linear? How can you tell?

G. Determining the slope & Intercept of a Linear Relationship

1. Press [STAT] to access the STAT menu.
2. Arrow right to (CALC) (the sub menu displays a number of relationships that could be used to fit the data)
3. Press [5] OR arrow down to 5. {This will select the (LinReg) = Linear regression option onto the Home screen}
4. Press [2nd] [L3] [,] [2nd] [L2] [ENTER]

Commands 3 and 4 above instruct the TI to do a Least Squares Fit (Linear Regression) on the x-data stored in L1 (the default) and the y-data stored in L2 (default). Note that if step 3 had been followed by [ENTER], the TI would have done a least squares fir on the x-data stored in L1 (the default) and the y-data stored in L2 (default).

• a = slope of the line
• b = y-intercept of the line
• r = correlation coefficient (a measure of how well this line fits the data, with 1.0 being perfect!)

1. Press [Y=].
2. Select Y1 if it isn't already selected.
3. Press [CLEAR] to delete any unwanted function.
4. Press [VARS]
5. Press [5] to access Statistics.
6. Arrow right to (EQ) since we want an equation.
7. Press [7] and the regression equation appears in the Y1 slot.
8. Press [GRAPH] and both the data and the line will be plotted.

H. Creating Extra Lists

1. Press [PRGM] (the program screen displays 3 menus plus a numbered list of all programs stored below, with the exception of any teacher protected programs.
2. Arrow over to (new) and press [ENTER]
3. Enter a name (let's all call it SCIENCE) at the prompt (Name= ) and press [ENTER]. (note that the TI is automatically in the ALPHA mode for this step)
4. Press [2nd] [Rcl] [2nd] [L1] [ENTER].
5. Press [2nd] [QUIT] and you should be back to the home screen.

1. Press [PRGM]
2. Arrow down until you have highlighted the program that you have created up above (Programs will be in alphabetical order) and press [ENTER]. (This ENTER selects the program SCIENCE from the program menu
3. Press [ENTER] (This ENTER runs the program & places the stored data into the current ANS register)
4. Press [STAT] in order to access the STAT screen.
5. Press [ENTER] in order to edit.
6. Arrow over/up to (L5) so that L5 at the top of the list is highlighted (assuming that this is where you want to place the previously stored data)
7. Press [2nd] [ANS] [ENTER] to store the data in the selected list.

I. Calculator to Calculator Link

Linking:

Set the receiving calculator:

Set the sending calculator:

Presenter(s) for this month's seminar:

Mark Case and John Hnatow

Emmaus HS, 851 North St., Emmaus, PA 18049