DETAILED DESCRIPTION OF THE INVENTION
[0011] FIG. 1 illustrates the front panel of a calculator 10 , which incorporates the features of the present invention. Calculator 10 is described herein in terms of particular software and hardware features of the TI-83+, a commercially available graphing calculator manufactured by Texas Instruments Incorporated. Apart from the features of the present invention, many of the features of calculator 10 described herein are typical of graphing calculators, while other features are unique to the TI-83+ “family” of TI calculators. The use of the TI-83+ is for purposes of description, and does not limit the invention. The features that are the subject of the present invention could be incorporated into other calculators that provide graphical displays, or they could be incorporated into other computer based teaching tools and handheld computers.
[0012] In FIG. 1 , the screen 11 of calculator 10 has a “graphical display”, as that term is used herein. In addition to the ability to draw graphical displays of various types, some of the software features of calculator 10 include software applications loading and storage, and keystroke programming. It also permits data collection, display and analysis.
[0013] Various hardware features include a large pixel screen 11 which is 64×94 pixels. A keypad 12 has various keys for data and command entry, some of which are used to implement the invention and are described herein. The calculator includes a processor 13 connected to a memory unit 14 having a 32K byte RAM and 512K byte application space. Other features are an I/O port for data linking, and a unit-to-unit link cable connection capability.
[0014] As is typical of calculators, calculator 10 has a secondary function key, 2nd key 12 a , which permits other keys to have two functions. For example, by pressing 2nd key 12 a and then STAT/LIST key 12 b , the calculator performs the LIST function. For simplicity of explanation herein, a key having two functions is referred to in terms of the function appropriate for the context, i.e., when discussing the LIST function, the STAT/LIST key 12 b is referred to as the LIST key 12 b . Similarly, calculator 10 has an Alpha key 12 c , which when depressed makes the other keys subsequently depressed to input an alpha character.
[0015] The present invention introduces a user interface and method, which is particularly directed to helping a student in a classroom environment. FIGS. 2 a - f illustrate an example of the screen displays of an embodiment of the present invention. This screen displays are for the calculator illustrated in FIG. 1 while running an application program stored in memory 14 by processor 13 . An embodiment is a user interface to allow the user to quickly and easily enter, plot and analyze data on a handheld device. The invention introduces a “wizard” user interface that smoothly guides the user through a sequential process of: entering data in one or more lists, viewing the data graphically using one of several common plots, viewing one or more regression functions to fit the data, and analyzing the data using common statistical measures. The invention is applicable and useful for other computer devices such as personal computers, personal data assistants or other hand held electronic devices.
[0016] The first screen display of an embodiment of the present invention is the menu display 110 shown in FIG. 2 a . The menu display 110 includes a title 112 , a list of menu selections 114 and soft keys 116 . The soft keys show which of the hard keys 117 on the calculator keyboard located directly below the indicator should be pressed to get the corresponding operation. In this preferred embodiment, the menu has menu selections for data entry, plotting and analyzing. In the preferred embodiment, when the user quits or exits from subsequent screens of any of these menu selections, the program or user interface returns to the menu screen 110 .
[0017] FIG. 2 b shows the screen display after the user presses the key below the “Data” soft key, which starts the “Data=New/Edit Data” menu option. This screen 118 allows the user to edit data in various lists using a list editor. The list editor displays data in a column-and-row format. Each column contains one list of data. The lists are labeled L1, L2, L3, L4, L5, and L6 120 (only 3 lists are shown). The labels can be changed, and more lists can be added to the list editor. Each row in a list contains one data element. The row label and its value are displayed on the entry/edit line 122 at the bottom of the screen. The user is able to enter data into the list element at the current cursor position, the active cell, indicated by the reverse video cursor 124 . The cursor is moved in the list editor, from list to list and element to element, with the arrow keys. New entries in the list replace the previous entry.
[0018] FIG. 2 c show the list editor after entering in data for lists L1, L2, and L3. Note the row label and value for the list element identified by the cursor are shown on the entry/edit line. In this figure, the entry/edit line shows that list 3 , item 6 contains the value “216.”
[0019] The contents of a list can also be generated using a formula entered at the list header. After entering a formula, the value of each list element is determined from the formula and then inserted into each cell in the list. FIG. 2 d show the list editor after moving the cursor to the list header for list L4 126 . The entry edit line now shows the contents of the list L4 as empty. The user can then fill the list by inserting a formula with references to another list and arithmetic operators. Pressing 2 nd followed by 3 enters the list name L3. Pressing the multiply operator followed by the number 2 results in the formula and display as shown in FIG. 2 e . Subsequently pressing the enter key results in the display shown in FIG. 2 f . The list L4 is now filled with numbers representing the contents of list L3 times two as shown in FIG. 2 f.
[0020] After the user has created one or more lists, the Data/Graphs Wizard allows the student to quickly and easily plot the data. For example, the user presses quit from the screen shown in FIG. 2 f to return to the entry screen as shown in FIG. 2 a . At this point, the user can now select the plot soft key 128 . The plot screen 150 is then displayed as shown in FIG. 3 a . The user can now select a plot type by pressing the key corresponding to the soft key for the desired type of plot. There are 4 plot types shown. The first two types require 2 variables and the last two require only 1 variable. The user must define a list for each variable needed by the plot. After selecting the plot type, the user will be asked to enter in the list for each variable.
[0021] From the display screen 150 shown in FIG. 3 a , pressing the soft key 152 corresponding to scatterplot will result in the screen shown in FIG. 3 b . Scatterplot plots the points independently on the graphing screen using two lists to provide the x and y values. The user now can select the list to provide the independent variable for the scatter plot by moving the cursor keys and pressing enter. In this case, the list L1 154 is selected for the independent variable. After pressing enter, the screen shown in FIG. 3 c is then displayed. Similarly, the user is allowed to choose the dependent variable for the scatter plot. The list L2 156 is selected by moving the cursor to L2 and pressing “enter.” The scatter plot is then displayed as shown in FIG. 3 d.
[0022] In a similar way, the user is can easily produce the other plot types from the plot menu 150 . From the display screen 150 shown in FIG. 3 a , the user can press the soft key 160 to plot an xy line using two lists of data to provide the x and y values. As described above, the user can select the list to provide the independent and dependent variables by moving the cursor keys and pressing enter (not shown). In this case, the list L1 is selected for the independent variable and L2 for the dependent variable. After making these two selections (not shown) and pressing enter, the screen shown in FIG. 3 e is then displayed with a line graph with the same data as the scatter plot described above.
[0023] The third type of plot in the plot menu 150 is the Modified box plot. From the display screen 150 shown in FIG. 3 a , the user can press the soft key 162 to select this plot type. The modified box plot lets the user view the distribution of elements within a single data set. Similar to the previous plot types, the user selects the list to provide the data input by moving the cursor keys and pressing enter (not shown). As an example, FIG. 4 a shows a list L1=(12, 92, 104, 132, 114, 110, 145, 85, 116, 108). After selecting modified box plot in screen 150 and then selecting the list L1 (not shown) the screen shown in FIG. 3 g is displayed. The minimum and maximum x are shown as the endpoints of the wisker lines 164 coming out of the box 166 . The box left and right edges represent the first and third quartile values respectively, and the line dividing the box is the median value of the data set. These values can be observed by pressing the trace key of the calculator as shown in FIG. 3 h . The other point values can be determined by moving the cursor to other points on the boxplot using the cursor keys.
[0024] The final plot type in the plot menu 150 is the histogram plot. From the display screen 150 shown in FIG. 3 a , the user can press the soft key 164 to select this plot type. The histogram lets the user graphically view the distribution of elements within a single data set. Similar to the previous plot types, the user selects the list to provide the data input by moving the cursor keys and pressing enter (not shown). The resulting plot show how many data elements fall within certain equally-spaced intervals. As an example, the data list shown in FIG. 4 a is again used. After selecting histogram plot in screen 150 and then selecting the list L1 (not shown) the screen shown in FIG. 3 i is displayed. The minimum, maximum and n are shown for each interval by pressing the trace key of the calculator as shown in FIG. 3 j . These values for the other intervals can be determined by moving the cursor to the other points on the histogram using the cursor keys as shown in FIG. 3 k.
[0025] Another feature of the present invention is fitting the graphed data to a regression to see how it fits into a curve. After a scatter plot or an xy line is graphed, the user is requested to choose a fit method. For example, from the screen displayed in FIG. 3 d , the user is requested to choose a fit method when exiting this screen. (Other keystrokes may not be recognized to maintain a limited functionality while in the data/graphs wizard.)
[0026] FIG. 4 a shows 9 fit methods. The LIN REG method displays a linear regression that fits the model y=ax+b to the data using a least squares fit. The EXP REG method displays an exponential regression that fits the model equation y=ab x to the data suing a least-squares fit and transformed values x and ln(y). The PWR REG method displays a linear regression that fits the model y=ax b to the data using a least squares fit and transformed values ln(x) and ln(y). The QUAD REG method displays an exponential regression that fits the second degree polynomial y=ax 2 +by+c to the data. The CUBIC REG method displays an cubic regression that fits the third degree polynomial y=ax 3 +bx 2 +cx+d to the data. The QUART REG method displays a quartic regression that fits the fourth degree polynomial y=ax 4 +bx 3 +cx 2 +dx+e to the data. The MED-MED method displays a median-median regression that fits the model equation y=ax+b to the data using the median-median line (resistant line) technique, calculation the summary points for x1, y1, x2, y2, x3 and y3. The LOGISTIC method fits the model equation y=c/(1+a*e −bx ) to the data using an iterative least-squares fit.
[0027] FIG. 4 b illustrates the LIN REG fit method applied to the data plot shown in FIG. 3 j . This screen results from exiting from the screen in FIG. 3 j , which results in the screen of FIG. 4 a , and then choosing the LIN REG method by using the cursor keys and pressing enter. Similarly, using the same data plot and choosing the EXP REG method results in the display as shown in FIG. 4 c.
[0028] Another feature of an embodiment of the present invention allows the user to analyze the data of a list. The STAT option is the third menu option available on the initial menu screen 110 shown in FIG. 2 a . The stat function is activated by pressing the key associated with the STAT soft key 129 . The STAT menu option performs statistical calculation on a single data set or list. After pressing the soft key 129 the user must select a list to analyze as shown in FIG. 5 a . After pressing enter, the first screen of statistical data is displayed as shown in FIG. 5 b . By pressing the down arrow key or other cursor key, the rest of the statistical calculation are displayed as shown in FIG. 5 c . The statistical calculations in the illustrated embodiment are a collection of standard statistical values. Other values could also be included. When the user exits from this screen, the user interface preferably returns to the menu screen 110 .
[0029] Other Embodiments
[0030] Although the present invention has been described in detail, it should be understood that various changes, substitutions, and alterations could be made hereto without departing from the spirit and scope of the invention as defined by the appended claims.
[0031] The described embodiment of the present invention is an application program on a graphing calculator, which allows the user observe a grid of real-time data and allows the user to easily make changes in the grid data while the program is operating. Similarly, other embodiments include the same user interface functionality in a ROM software application package that is executed on a graphing calculator or other handheld device.