TI-82: Lists and Statistics

There are two features of the TI-82 calculator that will be used. Lists and Statistics. The STAT key is located at the top center of the calculator and the LIST key is obtained by 2^nd STAT.

There are six lists that you can work with at any time on the calculator. Each set of data requires a list. If you include frequencies for the frequency distribution, then it will require a list for the data and a separate list for the frequencies. The lists are labeled L1, L2, L3, L4, L5, and L6 and are accessed on the calculator by pressing "2^nd 1", "2^nd 2", etc.

STATS Key

STAT has two major categories, EDIT and CALC

STAT-EDIT

1. Edit - Use this to enter data into a list.
2. SortA( - This will sort a list in ascending order. This is useful if you want to find the frequencies after you have already established the limits or boundaries. Since the data is sorted in order, you just have to go through and count the number in each class. You don't need to do the tally. This will replace the list you tell it sort.
3. SortD( - This will sort a list in descending order. This will replace the list you tell it to sort.
4. ClrList - This will erase any existing lists.

STAT-CALC

1. 1-Var Stats - This is used when there is only one variable. It will handle both raw data and frequency distributions.
2. 2-Var Stats - This is used when there are two variables, and x and y. This won't happen until the end of the semester.
3. Setup - You will need to check the setup before you find any other statistical values from this menu. It allows you to specify which list(s) you put the data into and if necessary, which list contains the frequencies.
4. Med-Med - A regression model that isn't used in this course.
5. LinReg(ax+b) - A regression model that will be used later in the course after we talk about two variable statistics.
6. QuadReg - A regression model that isn't used in this course.
7. CubicReg - A regression model that isn't used in this course.
8. QuartReg - A regression model that isn't used in this course.
9. LinReg(ax+b) - A regression model that will be used later in the course after we talk about two variable statistics. The book uses this model, however, we will use #5 instead.
10. LnReg - A regression model that isn't used in this course.
11. ExpReg - A regression model that isn't used in this course.
12. PwrReg - A regression model that isn't used in this course.

LIST Key

The LIST command has two major sections, OPS (Operations) and MATH.

LIST-OPS

1. SortA( - This will sort a list in ascending order. This command is equivalent to the SortA( command under the STATS key.
2. SortD( - This will sort a list in descending order. This command is equivalent to the SortD( command under the STATS key.
3. dim - This function will return the dimensions of a list. The dimension of a list the number of elements in the list. This is also used as a command to set the dimensions of a list.
4. Fill( - This command will fill a list with a constant. This is useful if you need to set an entire list to all be one number.
5. seq - This function will generate a sequence of numbers according to the function specified as the first argument. A list is returned, but you must save it to one of the six lists if you want to use it for anything.

LIST-MATH

1. min( - Returns the minimum value in a list.
2. max( - Returns the maximum value in a list
3. mean( - Returns the arithmetic mean of all numbers in the list. The mean is the sum of the list divided by the dimension of the list.
4. median( - Returns the median of the list. The median is the middle number when the list is sorted in ascending order. If the dimension is an even number, the median is the midpoint between the two middle values when the list is sorted in ascending order.
5. sum - Returns the sum of the values in the list.
6. prod - Returns the product of the values in the list. If the product of a list is zero, then at least one of the numbers is zero.

Other Keys

VARS

The VARS key can be used to retrieve the value of a statistic.

VARS Statistics

This will save a lot of retyping of values and allow you to use the full accuracy of the calculator instead of losing digits when re-entering numbers.

Here are some common values you will be using:

There are other values under statistics which you will use. You may have to arrow to other submenus first for some of them.

STORE

This key will save values. You may save a scalar value to a real variable (A-Z) or a list value to a list (L1 - L6). You can use the STORE key to save a value to the dimension of a list to set its size. You can use the STORE key to save a list generated by the sequence command to a list.

Mathematical Operations and Functions

Lists can be used as arguments of functions. If they are, the function is applied to each element in the list. Mathematical operations can be performed on lists. For more information on lists, see the Introduction to the TI-82.

Entering Data

Always start with a clean set of data. You don't want to mix data from one problem with data from another problem. Before starting any new problem, you should clear out existing data.

STAT ClrList L1,L2,L3

Another way to clear the lists is to go into STAT EDIT, arrow to the top so that the list name is highlighted. Then press the CLEAR key and ENTER.

You may only need to specify one list, but you can specify more than one, just separate them with commas.

After the lists have been cleared, you can enter the new lists:

STAT Edit

Select this list that you want to use. The default will be L1. This will be fine for most things, but do realize you can use any of the lists. Just be sure to check the setup later.

Type in each number separating them by enter. When you are done entering, press the QUIT key (2^nd MODE).

If you need to correct data, just go back to STAT EDIT without clearing the list first.