The position of the graphically represented keys can be found by moving your mouse on top of the graphic.
| Turn your calculator on | |||||||||
Press  . |
|||||||||
| Clearing the memory | |||||||||
To clear the entire memory, press 
(you should see STAT written above the key) 
. The word
DATA should be highlighted. Press 
(labeled ClrStat) and  .
The screen should say
done. |
|||||||||
| Entering data | |||
| one variable | |||
Press
(STAT) button to
enter statistics mode. Press
(the word DATA should
be highlighted). Press 
(labeled 1:Edit). Enter the first number and press
(twice) (screen has y values, we must hop over them). Enter the second
number, press
(twice). Continue until all the data has been entered.
|
|||
| two variables | |||
| Press
to
enter statistics mode. Press
(the word DATA should
be highlighted). Press
(labeled 1:Edit). Enter the first x-value, then press .
Enter the corresponding y-value, the press .
Continue until all of the data has been entered. |
|||
| Calculating one-variable statistics | ||||
| mean (x) | ||||
|
Press
. The word CALC should be highlighted. Press
(labeled 1:1-Var)
and .
The mean is x.
|
||||
| standard deviation for populations (s or sn) | ||||
| Press
. The word CALC should be highlighted. Press
(labeled 1:1-Var)
and .
The population standard deviation is
sx. |
||||
| standard deviation for samples (s or sn-1) | ||||
| Press
. The word CALC should be highlighted. Press
(labeled 1:1-Var)
and .
The sample standard deviation is sx. |
||||
|
Calculating two-variable statistics |
|||||
| r (correlation) | |||||
|
Press
. The word CALC should be highlighted. Press
(labeled 2:LinReg)
and .
The correlation coefficient is r.
|
|||||
| regression coefficients | |||||
| slope | |||||
| Press
.
The word CALC should be highlighted. Press
(labeled 2:LinReg)
and .
The slope is a. |
|||||
| y-intercept | |||||
| Press
. The word CALC should be highlighted. Press
(labeled 2:LinReg)
and .
The y-intercept is b. |
|||||
| Calculating combinations and permutations | ||||
| combinations (nCr) | ||||
Enter the n value. Press  .
On the
top, you'll see four choices. Use
to move the cursor to PROB, the fourth choice. Press  (labeled
nCr). Enter the r value, then press . |
||||
| permutations (nPr) | ||||
| Enter the n value. Press .
On the
top, you'll see four choices. Use
to
move the cursor to PROB, the fourth choice. Press
(labeled nPr). Enter the r value, then press . |
||||
| Turning the calculator off | ||
|
Press
(you should see OFF above the key).
|
||
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: Clear Memory |
|
| 2: Enter Data |
(QUIT) |
| 3: Compute the mean |
(CALC)
(1:1-Var) |
| 4: Compute the standard deviation (population) |
(CALC)
(1:1-Var) |
| 5: Compute the standard deviation (sample) |
(CALC)
(1:1-Var) |
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: Clear Memory |
|
| 2: Enter Data |
 |
| 3: Compute the slope of the regression line |
(2:LinReg) |
| 4: Compute the y-intercept of the regression line |
(2:LinReg) |
| 5: Compute the correlation |
(2:LinReg) |
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.
| 1: Compute 10C6 |
(3: nCr) |
| 2: Compute 9P5 | 
(2:nPr) |
You should get 10C6 = 210 and 9P5=
15120.
Other TI-81 Pages: