The position of the graphically represented keys can be found by moving your mouse on top of the graphic. 

Turn your calculator on
Press Bottom Left Corner. 
Clearing the memory
This is not that much an issue as the TI-89 has tons of memory. Simply give your new list a different name. However, you cannot use a name if it's already in use, so you might want to delete a list if you're done with it. Press  Row 1, Column 1 Row 7 Column 5 (it says VAR-LINK above the key). Press until the cursor is on the list you want to delete. Press First in the top row of buttons under the screen Row 8, Column 2. Delete any other lists, if necessary. Then press Row 1, Column 3 to get back to the main screen.

 

Entering data
one variable
Press Row 2, Column 3.  A menu will appear on the screen.  Press Row 7, Column 4 (Data/Matrix Editor), then press Row 8, Column 4 (New).  You'll see a window that says Type:.  If it already says Type: Data, press to accept.  If not, press to view the other options and pick Data then press to accept.  The cursor should now be on  Folder: Main.  Press to accept.  Pick an arbitrary name (say M) for the list. If it's in use, either choose another name or delete the list (see above for instructions). To choose M, type Row 2, Column 2 Row 7, Column 3 (you should see M above the 5 key).  Then press Bottom Right Corner Bottom Right Corner (twice) to accept and verify the name.  A table should appear with c1, c2, c3 over the columns.  Use c1 for one variable data.  Enter the first number.   Press Bottom Right Corner.  Enter the second number.  Press Bottom Right Corner.   Continue until all the data has been entered.
two variables
Press Row 2, Column 3.  A menu will appear on the screen.  Press Row 7, Column 4 (Data/Matrix Editor), then press Row 8, Column 4 (New).  You'll see a window that says Type:.  If it already says Type: Data, press to accept.  If not, press to view the other options and pick Data then press to accept.  The cursor should now be on  Folder: Main.  Press to accept.  Press  Row 2, Column 2 row 5, column 4 (D) (we're calling our dataset D; call it whatever you want using the alpha-numeric keys; if you want to delete a list so you can reuse the name, use the Clear Memory instructions above).  Then press (twice) to accept and verify the name.  A table should appear with c1, c2, c3 over the columns.   Use c1 for the x-variable.   Enter the first x-value, then press .  Enter the second x-value, then .  Continue until all the x-values have been entered . Press to move the cursor to c2 for the y-variable.  Press as many times as necessary to get the cursor next to the first x-value. Enter the first y-value, then .  Enter the second y-value, then . Continue until all the y-values have been entered.  Make sure they line up with the corresponding x-values. 

 

Calculating one-variable statistics
mean (x)
Press ( CALC).  You'll see a row that says calculation type.  Press .  Press Row 8, Column 2 (for One Var).  Press . You'll see x........and a box. Type Row 2, Column 2 Row 5 Column 3 (for C). Press and you'll see a chart. The first item in the chart is x, the mean.
standard deviation for populations (s or sn)
Press ( CALC).  You'll see a row that says calculation type.  Press .  Press Row 8, Column 2 (for One Var).  You'll see a screen with  x, Sx, Sx2, etc.  Oddly enough, sx for the population is not on the list.  However, it has been calculated.  To locate it, return to the home screen by pressing Row 2, Column 3 Row 8, Column 2.  At the bottom of the screen, type in Row 2 Column 1 Row 2, Column 2 (s), Row 4 Column 1, then Bottom Right Corner.  On the screen, you'll see sx.
standard deviation for samples (s or sn-1)
Press ( CALC).  You'll see a row that says calculation type.  Press .  Press Row 8, Column 2 (for One Var).  Press . You'll see x........and a box. Type Row 2, Column 2 Row 5 Column 3 (for C). Press and you'll see a chart. Look for sx - that's the sample standard deviation.

Calculating two-variable statistics
r (correlation)
Press (CALC).  You'll see a row that says calculation type.  Press Row 7, Column 3 (for Lin Reg).  Press Row 2, Column 2 Row 5 Column 3 (for c) Row 2, Column 2 Row 5 Column 3 Row 8, Column 3 Bottom Right Corner to tell the calculator which variables to do the regression on.  Then press Bottom Right Corner again to tell it to run the regression.  You'll see a screen with a =, b =, corr =,  R2 = .  The corr is what we're looking for here.  R2 is the square of the correlation.
regression coefficients
slope
Press (CALC).  You'll see a row that says calculation type.  Press Row 7, Column 3 (for Lin Reg).  Press Row 2, Column 2 Row 5 Column 3 (for c) Row 2, Column 2 Row 5 Column 3 Row 8, Column 3 Bottom Right Corner to tell the calculator which variables to do the regression on.  Then press Bottom Right Corner again to tell it to run the regression.  You'll see a screen with a =, b =, corr =,  R2 = .   The b value is the slope of the regression line. 
y-intercept
Press (CALC).  You'll see a row that says calculation type.  Press Row 7, Column 3 (for Lin Reg).  Press Row 2, Column 2 Row 5 Column 3 (for c) Row 2, Column 2 Row 5 Column 3 Row 8, Column 3 Bottom Right Corner to tell the calculator which variables to do the regression on.  Then press Bottom Right Corner again to tell it to run the regression.  You'll see a screen with a =, b =, corr =,  R2 = .  The a value is the y-intercept. 


Calculating combinations and permutations
combinations (nCr)
Press Row 1, Column 1 Row 7, Column 3 (MATH is written above the key).  You should see several options on the screen.  Press Row 6, Column 2 (PROB).  You will see more options.   nCr is the third option, so press Row 8, Column 4.  Enter the n value, then press Row 5 , Column 4.  Enter the r value, then press the Row 5 - Column 3 key.  Finally press Bottom Right Corner.
permutations (nPr)
Press Row 1, Column 1 Row 7, Column 3 (MATH is written above the key).  You should see several options on the screen.  Press Row 6, Column 2 (PROB).  You will see more options.   nPr is the second option, so press .  Enter the n value, then press Row 5 , Column 4.  Enter the r value, then press the Row 5 - Column 3 key.  Finally press Bottom Right Corner.

 

Turning the calculator off
Press Row 1, Column 1 Bottom Left Corner.

 

Worked Out Examples

In the following examples, we list the exact key sequence used to find the answer.  We will list the keys by the main symbol on the key.  In parentheses, we will list a helpful mnemonic, e.g. we will list ex as (ex).

A: What is the mean and standard deviation of the following list of numbers?

15      16      20      21

1: To start  Row 1, Column 1 Row 7 Column 5 (VAR-LINK) (as necessary) First in the top row of buttons under the screen Row 8, Column 2 Row 1, Column 3 
2: Enter Data Row 2, Column 3 Row 7, Column 4 Row 8, Column 4 Row 2, Column 2 row 5, column 4 (D, although this is arbitrary)  Row 8, Column 2 Row 7, Column 3 Bottom Right Corner Row 8, Column 2 Row 7, Column 4 Bottom Right Corner Row 8, Column 3 Row 9, Column 2 Bottom Right Corner Row 8, Column 3 Row 8, Column 2 Bottom Right Corner  
3: Compute the mean   Row 8, Column 2 . You'll see x........and a box. Type Row 2, Column 2 Row 5 Column 3 (for C). Press  
4: Compute the standard deviation (population) Row 2, Column 3 Row 8, Column 2 Row 2 Column 1 Row 2, Column 2 (s) Row 4 Column 1 Bottom Right Corner
5: Compute the standard deviation (sample)   Row 8, Column 2 . You'll see x........and a box. Type Row 2, Column 2 Row 5 Column 3 (for C). Press


    You should get a mean of 18, population standard deviation of 2.549509757 and a sample standard deviation of 2.943920289.

B: Find the linear regression line for the following table of numbers. Also find the correlation.

x 1 2 3 4
y 2 4 5 7

1: To start  Row 1, Column 1 Row 7 Column 5 (VAR-LINK) (as necessary) First in the top row of buttons under the screen Row 8, Column 2 Row 1, Column 3  Row 2, Column 3 Row 7, Column 4 Row 8, Column 4   Row 2, Column 1 It's Blue row 5, column 4 Bottom Right Corner Bottom Right Corner
2: Enter Data  Row 2, Column 3 Row 7, Column 4 Row 8, Column 4 Row 2, Column 1 It's Blue row 5, column 4 (D, but this is arbitrary) Bottom Right Corner Bottom Right Corner Row 8, Column 2 Bottom Right Corner Row 8, Column 3 Bottom Right Corner Row 8, Column 4 Bottom Right Corner Row 7, Column 2 Bottom Right Corner   Row 8, Column 3 Bottom Right Corner Row 7, Column 2 Bottom Right Corner Row 7, Column 3 Bottom Right Corner Row 6, Column 2 Bottom Right Corner
3: Compute the slope of the regression line   Row 7, Column 3 Row 2, Column 2 Row 5, Column 3 Row 8, Column 2 (C1) Bottom Right Corner
  Row 2, Column 2 Row 5, Column 3 Row 8, Column 3(C2) Bottom Right Corner Bottom Right Corner  
4: Compute the y-intercept of the regression line   Row 7, Column 3 Row 2, Column 2 Row 5, Column 3 Row 8, Column 2 (C1) Bottom Right Corner
  Row 2, Column 2 Row 5, Column 3 Row 8, Column 3(C2) Bottom Right Corner Bottom Right Corner  
5: Compute the correlation   Row 7, Column 3 Row 2, Column 2 Row 5, Column 3 Row 8, Column 2 (C1) Bottom Right Corner
  Row 2, Column 2 Row 5, Column 3 Row 8, Column 3(C2) Bottom Right Corner Bottom Right Corner  


    You should get a slope of 1.6, a y-intercept of 0.5, and a correlation of 0.992277876.
    The regression line would be: y = 1.6x+0.5.

C: Find 10C6 and 9P5.
1: Compute 10C6  Row 1, Column 1 Row 7, Column 3 (MATH) Row 6, Column 2 (PROB) (nCr) Row 8, Column 2 Row 5 - Column 4 Row 5, Column 3 Bottom Right Corner
2: Compute 9P5   Row 1, Column 1 Row 7, Column 3 (MATH) Row 6, Column 2 (PROB) Row 8, Column 3 (nPr) Row 6, Column 4 Row 5 - Column 4 Row 7, Column 3 Row 5, Column 3


You should get 10C6 = 210 and 9P5= 15120.

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