Entering Data in the TI-81 calculator

You will be using the statistics mode of the calculator to enter data and examine the results.

1) Turn your calculator on.

2) Press 2nd and then STAT (above MATRX). Move the arrow to DATA and select CLR STAT. Press ENTER.

You should see ClrStat on the screen. Press ENTER again and the screen should read DONE. We are removing any old data that might have been left on the screen.

3) Press 2nd and then STAT. Move arrow to DATA, select EDIT, and then press ENTER.

4) We are going to be entering the following test grades:

90, 100, 75, and 50

We will put the grades in x1, x2, x3, and x4. Do not worry about y1, y2, y3, and y4 - this represents the frequency of occurrence of the the x-value . Leave it "1" for now.

Enter x1 = 90 y1 = 1
Enter x2 = 100 y2 = 2
Enter x3 = 75 y3 = 3
Enter x4 = 50 y4 = 4

5) Once you have entered the value for x4, press 2nd and then QUIT. We are going to allow the calculator to calculate the statistics for us. Press 2nd and then STAT, and move the arrow down to 1-VAR. Record the results below:

1)________________ symbol______

2)________________ symbol______

3)________________ symbol______

4)________________ symbol______

5)________________ symbol______

6)________________ symbol______

6) Can you figure out what the first symbol means? __________________

7) What do you think the last symbol means? _______________________

8) What do you think the second symbol means? ____________________

9) What is the average of the test grades? __________________________

10) Enter the following grades and determine the average using the calculator:

77 86 92 64 0 56 33 32 100 78

The average of the test scores is____________.