The Radio Shack EC-4043 has the exact same layout as the TI-36X.

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

Turn your calculator on
Press Top Right Corner.
Clearing the memory
Press Top Right Corner (AC stands for all clear).

 

Entering data
one variable
Press Row 1, Column 1 It's Blue Row 3 - Column 1 (you should see STAT1 above the key) to select the one-variable statistics mode.  The word STAT should appear on the screen.  Type in the first number and press Row 4, Column 1 (if you wish to delete the element after you hit the Row 4, Column 1, type it in again and press Row 4, Column 1 (S- ). You will see a 1 on the screen because, so far, you have entered one data point.  Type in the second number and press Row 4, Column 1.  Continue until all the data has been entered.
two variables
Press Row 1, Column 1 It's Blue Row 4, Column 1 (you should see STAT2 above the key) to select the two-variable statistics mode.  The word STAT should appear on the screen.  Enter the first x-value, then press the Row 3 - Column 1 key.  Enter the corresponding y-value, then press Row 4, Column 1.  Continue until all the data has been entered.

 

Calculating one-variable statistics
mean (x)
Press Row 2, Column 1 It's Yellow Row 3, Column 3 (you should see x above the key).
standard deviation for populations (s or sn)
Press Row 2, Column 1 It's Yellow Row 3, Column 5 (you should see sxn above the division sign).
standard deviation for samples (s or sn-1)
Press Row 2, Column 1 It's Yellow Row 3 , Column 4 (you should see sxn-1above the square root sign).

Calculating two-variable statistics
r (correlation)
Press Row 1, Column 1 It's Blue Row 6, Column 2 (you should see COR written above the key).
regression coefficients
slope
Press Row 2, Column 1 It's Yellow Row 6, Column 3 (you should see SLP written above the 5).
y-intercept
Press Row 2, Column 1 It's Yellow Row 6, Column 2 (you should see ITC written above the 4).


Calculating combinations and permutations
combinations (nCr)
Enter the n value.  Press Row 3 - Column 1. Enter the r value. Press Row 1, Column 1 It's Blue Bottom Left (you should see nPr over the arrow and nCr above the key).
permutations (nPr)
Enter the n value.  Press Row 3 - Column 1. Enter the r value. Press Row 2, Column 1 It's Yellow Bottom Left (you should see nPr over the arrow and nCr above the key).

 

Turning the calculator off
This is a solar calculator.  It does not turn off.  (If you cover it, it will turn off by itself in about two minutes).

 

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   Top Right Corner 
2: Enter Data   Row 1, Column 1 It's Blue Row 3 - Column 1 Row 7, Column 2 Row 6, Column 3 Row 4, Column 1 Row 7, Column 2 Row 6, Column 4 Row 4, Column 1 Row 7, Column 3 Row 8, Column 2  
 Row 4, Column 1 Row 7, Column 3 Row 7, Column 2 Row 4, Column 1 
3: Compute the mean  Row 2, Column 1 It's Yellow Row 3, Column 3 (x)
4: Compute the standard deviation (population)  Row 2, Column 1 It's Yellow Row 3, Column 5 (sxn)
5: Compute the standard deviation (sample)   Row 2, Column 1 It's Yellow Row 3 , Column 4 (sxn-1)


    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   Top Right Corner  
2: Enter Data  Row 1, Column 1 It's Blue Row 4, Column 1 (STAT 2) Row 7, Column 2 Row 3 - Column 1 Row 7, Column 3 Row 4, Column 1 Row 7, Column 3 Row 3 - Column 1  
  Row 6, Column 2 Row 4, Column 1 Row 3 - Column 1 Row 4, Column 1 Row 3 - Column 1 Row 4, Column 1
3: Compute the slope of the regression line   Row 2, Column 1 It's Yellow Row 6, Column 3 (SLP)
4: Compute the y-intercept of the regression line   Row 2, Column 1 It's Yellow Row 6, Column 2 (ITC)
5: Compute the correlation  Row 1, Column 1 It's Blue Row 6, Column 2 (COR)


    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 7, Column 2 Row 8, Column 2 Row 3 - Column 1 Row 6, Column 4 Row 1, Column 1 It's Blue Bottom Left (nCr) 
2: Compute 9P5  Row 5, Column 4 Row 3 - Column 1 Row 6, Column 3 Row 2, Column 1 It's Yellow Bottom Left (nPr)


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

Go to: 

sample problem set Home page
1