Using the Formula Editor

The Formula Editor is used to create custom formulas for the Final Grade in a Formula System gradebook and for Formula type grade items in Points, Weighted, or Formula System gradebooks.

To access the Formula Editor for the final grade in a Formula System Gradebook:

1. Click Grades in the NavBar.
2. Click Manage Grades (left).
3. At the bottom of the grade items list, click the first final grade link (Calculated Final Grade).
4. Click Edit Using the Formula Editor.

To access the Formula Editor in a Formula type grade item:

1. Click Grades in the NavBar.
2. Click Manage Grades (left).
3. Click on the Formula type grade item name.
4. Click Edit Using the Formula Editor.

You are now ready to create your formula.

Navigating through the Formula

You can navigate through the formula by using your mouse to change the cursor position, by using the arrow keys on your keyboard, or by using ICON's move cursor buttons:

You can use these cursor buttons to move to the beginning of the formula, to one place left or right of your current cursor position, or to the end of the formula.

Entering the Formula

1. Begin by selecting one of the following functions in the drop-down menu next to Function:
   • SUM {a,b,c, ...} adds a series of values together. These values may be real numbers; numeric, pass/fail, selectbox, or formula grade items; or functions.
   • AVG {a, b, c, ...} calculates the average of a series of values. These values may be real numbers; numeric, checkbox, selectbox, or formula grade items; or functions.
   • MAX {a, b, c, ...} returns the largest value in a series of values. These values may be real numbers; numeric, checkbox, selectbox, or formula grade items; or functions.
   • MIN {a, b, c, ...} returns the smallest value in a series of values. These values may be real numbers; numeric, checkbox, selectbox, or formula grade items; or functions.
   • IF {condition, then x, else y} creates and if-then-else statement. If the condition is true, then x is returned. If the condition is false, then y returned.
     • The condition must be a Boolean statement.
     • The values for x and and y may be real numbers; numeric, checkbox, selectbox, or formula grade items; or functions.
   • NOT {condition} inverts true and false. If the condition is true, then a false statement is returned. If the condition is false, then a true statement is returned.
     • The condition must be a Boolean statement.
2. Click Start. The name of the function and the opening bracket will be inserted into the formula, e.g., SUM {.
3. Select a Grade item. (Note: Calculated and Text item types cannot be used in formulas.)
4. Select Points Received, Max Points, or Percent:
5. Click Insert.
6. Click Next Term.
7. Repeat steps 3 and 4 until all grade items are entered.
8. Click End. The closing bracket will be inserted into the formula.

Note: Functions may be nested inside other functions, using parenthesis as appropriate. For example, you could nest a SUM function inside an IF function: IF{SUM{[Quiz1.UserGrade], [Quiz2.UserGrade]}>=20, then 100, else 0}.

Numbers and Mathematical Operators

Enter numbers and mathematical operators using the buttons at left or the corresponding keys on your keyboard.

Other Operators

Enter the Boolean operators And and Or as well as parenthesis and comparison operators using the buttons at left. Parenthesis and comparison operators can also be entered by using the corresponding keys on your keyboard. Comparison Operators: = Equal to <> Not equal to < Less than > Greater than <= Less than or equal to >= Greater than or equal to

Removing Items from the Formula

You can remove items from the formula by using your mouse to change the cursor position and then pressing the backspace or delete key on your keyboard, or by clicking the Backspace or Clear buttons on the screen. You cannot remove items by highlighting the text and pressing the backspace or delete key.

IMPORTANT: Clicking the Backspace button deletes the single item to the left of the cursor. Clicking the Clear button deletes the entire formula.

Validating the Formula

You can validate the formula at any time by clicking the Validate button (top left). Clicking Validate checks the formula syntax. If the syntax is valid, the message "Formula Validated Successfully" appears in blue above the formula box. If the formula is invalid, an error message is displayed, and the cursor moves to the position in the formula where the error was detected (the formula element nearest to the error is highlighted in red).

Examples of validation errors:

• Unexpected token type--an unexpected token has been entered into the formula.
  • [Quiz2.UserGrade]4 as oppposed to [Quiz2.UserGrade]*4
• Unexpected terminal - a comma (or another makr) is missing from a formula statement
  • {[Quiz2.UserGrade][Quiz3.UserGrade]}
• Unbalanced parenthesis--an open parenthesis or bracket was entered into the formula without the accompanying close parenthesis or bracket.
  • SUM {[Quiz1.UserGrade], [Quiz2.UserGrade]
• Invalid number of operator paramaters--an operator (such as + or *) does not have the required number of parameters to be completed.
  • [Quiz1.UserGrade] +
• Invalid number of function parameters--the function does not contain the required number of terms
  • SUM{}
  • IF{[Quiz1.UserGrade] > 5, 10}
  • NOT{[Quiz1.UserGrade] < 5, [Quiz2.UserGrade] < 8}
• Numeric value expected--a numeric value has not been entered (a Boolean statement is in the place of a numeric value).
  • IF{[Quiz1.UserGrade] >10, 5 OR 7, 0}
  • SUM {[Quiz1.UserGrade <> 20], [Quiz2.UserGrade]}
• Boolean value expected--a Boolean statement has not been entered for the condition.
  • NOT{4}
  • IF{MIN{4,5}, 100, 0}

Validating, Previewing and Inserting the Formula

To validate the formula, click Validate (top left).

Clicking Preview (top left) also validates the formula and, if the validation is successful, opens a pop-up window in which the formula is applied to the first 10 students in the Grades List.

Clicking the Insert button (bottom right) validates the formula and, if the validation is successful, inserts the formula into your gradebook then closes the Formula Editor window.

22 May 2008