User manual TEXAS INSTRUMENTS TI-82 STATS GUIDEBOOK

[. . . ] Matrices - enter and save up to 10 matrices and perform standard matrix operations on them. Lists - enter and save as many lists as memory allows for use in statistical analyses. Statistics - perform one- and two-variable, list-based statistical analyses, including logistic and sine regression analysis; plot the data as a histogram, xyLine, scatter plot, modified or regular box-and-whisker plot, or normal probability plot. The CD included with your TI-82 STATS package also includes an electronic guidebook, which is a complete reference manual for the TI-82 STATS. If the CD is not available, you can download a copy of the electronic guidebook from the Texas Instruments web page at education. ti. com/guides 1 About this book This Getting Started Guide was designed for: students who are using a graphing calculator for the first time. [. . . ] Although it does not affect the calculation, it is frequently helpful to clear the previous work from the home screen before you begin a new problem. As you work through this guide, we recommend that you press ` each time you begin a new Example. This removes the previous example from the home screen and ensures that the screen you see matches the one shown in the example. y5 If you accidentally press a menu key, pressing ` will sometimes return you to the home screen, but in most cases you must press y 5 to leave the menu and return to the home screen. 8 Entering an expression An expression consists of numbers, variables, operators, functions, and their arguments that evaluate to a single answer. To enter a function or instruction on the entry line, you can: Press its key, if available. For example, press y N, press to move down to log(, and press to select log(. For example, to find the round function, press , press ~ to select NUM, then select 2:round(. Enter and evaluate the expression p Q 2. Press Result Example: yB2 9 TI-82 STATS menus Many functions and instructions are entered on the home screen by selecting from a menu. To select an item from the displayed menu: For more details, see Guidebook Chapter 1. Press the number or letter shown at the left of that item. -- or -- Use the cursor arrow keys, or }, to highlight the item, and then press . Some menus close automatically when you make a selection, but if the menu remains open, press y 5 to exit. Do not press ` to exit, since this will sometimes delete your selection. Example: Enter Press 3 27 on the home screen entry line. Result Menus containing an arrow next to the final item continue on a second page. 4 -- or -- 27 10 TI-82 STATS menus (continued) Example: Change the FORMAT menu setting to display grid points on the graph. Press Result y. ~ s Example: Turn off the display of grid points. y. The negative symbol is raised and slightly shorter. 16 Using parentheses Since all calculations inside parentheses are completed first, it is sometimes important to place a portion of an expression inside parentheses. For more details, see Guidebook Chapter 3. Example: Multiply 4*1+2; then multiply 4*(1+2). Press Result 412 412 Note: The closing parenthesis is optional. The exception to this rule occurs when there is another operation following the parenthetical operation. In this case, you must include the closing parenthesis. 17 Using parentheses (continued) Example: Divide 1/2 by 2/3. Press Result 12 23 Example: Calculate 16 ^ 2 . Press Result 1 16>12 Example: Calculate (L3)2. Press Result 3 Note: Try each of these examples without the parentheses and see what happens! 18 Storing a value Values are stored to and recalled from memory using variable names. Example: Store 25 to variable A and multiply A by 2. Press Result 2 5 [A] 2 [A] -- or -- [A] 2 19 Storing a value (continued) Example: Find the value of 2X3 - 5X2 - 7X + 10 when X = M0. 5. Press Result 5, , (stores L. 5 to X) 2, , >3 5, , 7, , 10 You can remove a value stored to a variable using the DELVAR function or by storing 0 to the variable. Example: Delete the value (L. 5) stored to X above by storing 0. Press Result 0, , , , 20 Graphing a function o Displays the Y= Editor, where you can enter one or more functions or expressions to graph. s Displays the graph you have defined. p Lets you set the viewing window to produce the best display of your graph. , , Lets you enter one of four symbols: X (if you are in Function mode), T (in Parametric mode), q (in Polar mode), or n (in Sequence mode). q Lets you quickly adjust the window to a predefined setting. r Lets you move the cursor along the graphed function using | and ~. 21 Graphing a function (continued) To graph a function, you must: 1. Display the graph. For more details, see Guidebook Chapter 3. Note: If you previously changed graph type in the mode settings, you must change the type back to Func (the default setting) before you graph. Example: Graph the function Y = X 2 + 1. Press Result o If Y1 is not blank, see Note. , , 1 s Note: If Y1 is not empty, press `. If there are additional entries in the Y= Editor, press ` until all are clear. 22 Changing mode settings The mode settings determine how entries are interpreted and how answers are displayed on the TI-82 STATS. Example: For more details, see Guidebook Chapter 1. Change the mode setting for decimals from Float to 3 decimal places. Press Result z ~~~~ y5 123456 Note: You must press to change a mode setting. If you highlight the setting and then exit the mode menu without pressing , the setting will not be changed. 23 Changing mode settings (continued) The mode menu includes the following settings: Setting Numeric notation Choices Normal: for example, 12345. 67 Sci (scientific): for example, 1. 2345674 Eng (engineering): for example, 12. 345673 Float: lets the number of decimal places change based on the result (up to 10 digits) Decimal 0 - 9: sets the number of decimal places to a value (0 - 9) that you specify Angle measure Type of graph Radian: interprets angle values as radians Degree: interprets angle values as degrees Func (functional): plots functions, where Y is a function of X Par (parametric): plots relations, where X and Y are functions of T Pol (polar): plots functions, where r is a function of q Seq (sequence): plots sequences Plot type Connected: draws a line connecting each point calculated for the selected functions Dot: plots only the calculated points of the selected functions Sequential or simultaneous graphing Real or complex mode Screen display Sequential: draws graphs one at a time Simul (simultaneous): draws all selected graphs at the same time Real: displays real numbers, such as 1, 1/2, 3 a+b (rectangular complex): displays as 3+2 re^q (polar complex): displays as re^q Full: displays full screen Horiz: displays a horizontal split screen G-T: displays a vertical split screen (graph & table) 24 Changing mode settings (continued) The importance of mode settings Example: Multiply 2/3 Q 2. Press Result z~ 232 Your first reaction to this example is that the calculator has produced a wrong answer. But you have set it to round to 0 decimal places (the nearest whole number), so for this setting the answer is correct. If you set rounding (decimals displayed) to 0 and then forget to reset it for later calculations, you may be surprised by some of your answers!With mode set to the default setting of Float, the result will be: Press Result 232 25 Setting the graphing window To obtain the best view of the graph, you may need to change the boundaries of the window. [. . . ] To enter a new value, you can start typing without pressing , but you must press to edit an existing value. 45 Using the MATRIX Editor (continued) Using matrices to solve systems of equations You can solve several equations simultaneously by entering their coefficients into a matrix and then using the rref (reduced rowechelon form) function. For example, in the equations below, enter 3, 3, and 24 (for 3X, 3Y, and 24) in the first row, and 2, 1, 13 (for 2X, 1Y, and 13) in the second row. Example: Solve and Press 3X + 3Y = 24 2X + Y = 13 Result ~~ 23 46 Using the MATRIX Editor (continued) Press Result 3324 2113 y5 ~ }}}}} 47 Using the MATRIX Editor (continued) Press Result You can interpret the resulting matrix as: [1 0 5] represents 1X + 0Y = 5 or X = 5 [0 1 3] represents 0X + 1Y = 3 or Y = 3 The solution to this system of equations is X = 5, Y = 3. 48 Error messages Occasionally, when you enter a function or instruction or attempt to display a graph, the TI-82 STATS will return an error message. For more details, see Guidebook Appendix B. Example: Enter the least common multiple function lcm( followed by only one number. Press Result ~}} 27 If you select 1:Quit, you return to the home screen with the cursor on a new entry line. If you select 2:Goto, you return to the original entry line; the cursor is flashing at the location of the error. You can find a complete list of error conditions with explanations in the Guidebook, Appendix B: General Information. 49 Resetting defaults If you are getting unexpected results, or if another person has used your calculator and may have changed the settings, you should consider resetting defaults on the TI-82 STATS. Press Result For more details, see Guidebook Chapter 18. yL 5 2 2 WARNING: If you reset All Memory in step 3 above, you will delete stored variables, lists, applications, and programs. [. . . ]