JMP Essentials. Curt Hinrichs
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| Note |
| Formatting decimal places affects what is viewed in the data table and in output but does not affect the precision of the data when used in calculations. |
Formatting Dates, Times, and Durations
Dates are numeric values in JMP, which allows them to be transformed into other date formats and calculated for duration or elapsed time. If you are importing data that contains dates, ensure that the data type is numeric.
The Column Info (Cols Column Info) window provides several date format options. (See Figure 2.29) When a date is selected from the Format menu, a secondary drop-down menu for the display format appears, along with a similar drop-down menu for the input format of your imported data. The format of your imported data needs to match one of JMP’s input format options, which can then be transformed into any format among the display format options.
Figure 2.29 Column Info Window for a Date Column
Let’s walk through a new example, TechStock, to illustrate this concept.
Example 2.3 TechStock
We will use the TechStock data table to illustrate dates in this section. This data set contains the stock price of the NASDAQ 100 (QQQ) at the high, low, and close for each trading day during the period 11/27/2000 to 2/26/2001. You can access this data set in the Sample Data folder that is installed with JMP: File Open C: Program Files SAS JMP 15 Samples Data Techstock.jmp.
1. Open the TechStock.jmp data table.
2. Click the Date column name.
3. Select Cols Column Info. Open the Format drop-down menu and select Date, which displays how the dates will appear in the data table.
4. It is currently displayed as d/m/y (see Figure 2.26), as indicated by the check mark. Change the format to Monddyyyy. Click Apply or OK. The date is now displayed as abbreviated month, day, and year in the Date column. (See lower part of Figure 2.30.)
Figure 2.30 Changing the Display Format of Dates
You can also format time and duration from this window provided you have these types of columns.
Column Properties Menu
Column Properties, another useful tool in the Column Info window (see Figure 2.31), enables you to add formulas, check ranges of values for auditing, and assign customized ordering to the data, among other tasks.
Figure 2.31 Column Properties
Some of the more commonly used column properties are:
● Missing Value Codes: used to identify values placed in columns that represent unknown (or missing) data. By default, JMP uses a blank cell for missing character data and a ∙ for missing cells in numeric columns. In cases where the original data used a different missing identifier (such as 999 or unknown), these values can be entered in the missing value codes property so that JMP recognizes the values as missing.
● Value Labels: used when values are entered into the data table rather than the actual label. For example, an analyst might code Low, Medium, High as 1, 2, 3 for ease of data entry. However, in analysis results, the labels are preferred. Using this property will enable you to enter the data as a code, but provide the labels in the appropriate display.
● Value Order: used to specify the order in which column values should be sorted. For example, using the order Poor, Good, Better, Best rather than the alphabetical ordering of these data values. An example is provided later in this section.
● Axis: allows the specification of axis properties (such as formatting, minimum value, maximum value, increment, tick marks, and grid marks) to be used for all graphs of the column.
These functions are described in detail in the Using JMP book (Help JMP Documentation Library Using JMP Ch. 5 Set Column Properties).
Formula Editor
JMP’s formula editor is handy and flexible. Use it when you need to create a new column that contains values that are calculated or derived from existing columns in your data table. You can also transform your data, add conditional statements, and much more. Due to the advanced nature of these features, we will cover only the most basic features here. For more information, see Using JMP at Help JMP Documentation Library Using JMP Ch. 5 Assign Column Properties.
One of the common operations performed with the Formula Editor is creating a new column of data that contains a calculation from existing columns. To illustrate this feature, let’s return to our Movies.jmp data table. For example, suppose we want to obtain the international revenues from these movies by subtracting the domestic revenues (Domestic $) from the worldwide revenues (Worldwide $).
1. First, we need to create a new column. Double-click in the column head to the right of our last populated column (Director). (See Figure 2.32.) Type “International $” in the heading, and press Enter. Click in the column head to highlight.
Figure 2.32 Creating a New Column
2. With the new column selected, select Cols Column Info. The Formula window appears in the Columns Properties menu. (See Figure 2.33.) Select Formula and Edit Formula. You see a list of columns or variables on the left side of the window.
Figure 2.33 Opening the Formula Editor
3. Click the Worldwide $ column, then the “-” symbol in the upper palette, and then the Domestic $ column. You see your formula take shape in the preview window. (See Figure 2.34).
Figure 2.34 Creating a Formula
4. When you click OK in the formula editor window, the calculated values appear in a new column in your data table.
5. Click OK in the Column Info window and you will see your new column, International $, within the Columns panel with a “+” next to it indicating that the column was created with a formula.
Value Order
The value order column property enables you to specify an order to the values of a categorical column. JMP’s built-in defaults order common ordinal columns such as months of the year or days of the week, but there are other instances when you would like to arrange responses (values) in some logical order for graphs and analyses. For example, some surveys have a range of responses from “Not Satisfied” to “Very Satisfied,” with a few intermediate responses in between. For specific examples of the built-in ordering, see the discussion of Column Properties in Using JMP.
In the Movies.jmp data table, we want to reorder the rating of the movies to display in this order: R, PG-13, PG, and G.
1. Click the Rating column. Select Cols Column Info, and then select Column Properties.
2. Select Value Ordering. (See Figure 2.35.) A new window appears with the available responses from the Rating column. Select a response and move it up or down or reverse the order, whichever is appropriate. Select Reverse for this example. (See Figure 2.36.)
Figure 2.35 Value Order-Column Properties Menu