- Calculated Formula Questions
- Before You Begin
- How to Create the Question and Formula
- Significant Figures
- How to Define the Variables
- How to Confirm the Variables and Answers
- About Setting Answer Options
Calculated Formula Questions
Calculated Formula questions present students with a question that requires them to make a calculation and respond with a numeric answer. The numbers in the question change with each user and are pulled from a range that you set. The correct answer is a specific value or a range of values. You may grant partial credit for answers falling within a range. Calculated Formula questions are graded automatically.
In this example, the numbers 6 and 9 are randomly generated from a range of values set by an instructor.
An instructor created this question by typing the following question text:
If a small glass can hold [x] ounces of water, and a large glass can hold [y] ounces of water, what is the total number of ounces in 4 large and 3 small glasses of water?
When a student views the question, the variables [x] and [y] are replaced with values that are generated randomly from number ranges that an instructor specifies.
Before You Begin
The process for adding a calculated question to an assessment has three steps:
- Create the question and formula
- Define the values for the variables
- Confirm the variables and answers
This question type allows you to randomize the value of variables in an equation, making it useful when creating math drills or testing students seated closely together.
How to Create the Question and Formula
- Access a test, survey, or pool. To learn more, see Tests, Surveys, and Pools.
- On the action bar, point to Create Question and click Calculated Formula.
- In the Question Text box, type the information that will appear to students. The question text must contain at least one variable. Surround variables with square brackets. Variables are replaced by values when shown to students.
Variables can be letters, digits (0-9), periods (.), underscores (_) and hyphens (-). Variables cannot contain the letters “e,” “i” and “pi” because they are reserved. Variable names must be unique, and you cannot reuse them. All other occurrences of the opening rectangular bracket (“[“) should be preceded by the back-slash (“\”).
- Type the Answer Formula. The formula is the mathematical expression used to find the correct answer. Choose operators from the buttons across the top of the Answer Formula box. In our example, the formula is 4y+3x.
The answer formula tool is written by WIRIS. To learn more, see the WIRIS manual [PDF].
The formula is not visible to students—it is used by Blackboard to determine the correct answer to the question.
- In the Options area, leave the Answer Range at zero if the answer must be exact. If you will allow a range of answers, set the answer options to define the range of full-credit answers. You can also Allow Partial Credit for a range of answers, and select Units Required.
To learn more, see About Setting Answer Options.
- Click Next to proceed.
Significant Figures in Calculated Formula Questions
Previously when instructors created Calculated Formula questions, they could only choose to have the formula calculate to a number of decimal places. This update allows the formula to calculate significant numbers.
When creating a Calculated Formula question, the instructor will now see the option to select Significant Figures under Answer Set options.
When the Instructor presses Calculate, the randomly generated variables will now display Significant Figures.
Note: Courses that are copied/restored that contain Calculated Formula questions will maintain the decimal values previously specified, but may be edited to change calculated answers to Significant Figures.
How to Define the Variables
The next page in the process defines the variables in the formula.
- In the Define Variables section, provide the Minimum Value and Maximum Value. When the question is presented to a student, Blackboard Learn replaces the variable with a value randomly selected from the range you defined. Optionally, select a decimal place using the Decimal Places drop-down list.
- In the Answer Set Options section, select the Decimal Places for Answer from the drop-down list. Students must provide the correct answer to this decimal place.
- Type the Number of Answer Sets. This determines the number of possible variations of the question that will be presented to students. You can also specify the number of decimal places and if the correct answer format is normal or exponential.
- Click Calculate to populate the answer sets.
How to Confirm the Variables and Answers
The last step in the process displays the answer sets in a table. Each answer set represents one of the possible variations of the question that can be presented to students.
- If needed, edit answer sets and click Calculate to update the list. Click Remove to the right of an answer set to delete it.
- Optionally, type feedback for correct and incorrect answers.
- Optionally, add question metadata. To learn more, see Question Metadata.
You must enable the options for feedback and metadata on the Question Settings page for those options to appear in individual questions.
- Click Submit and Create Another -OR- Submit to add the question to the test.
About Setting Answer Options
Options for partial credit and units appear after you select the check box for Allow Partial Credit or Units Required.
In the preceding example:
- An answer that is within plus or minus 4 is awarded 100% of the point total.
- An answer that is within the partial credit range of plus or minus 5 to 8 is awarded 50% of the point total.
The available options are:
- Answer Range: The range of answers that are awarded full credit. Select whether it is a Numeric range or a Percentage range. If the answer must be exact, type zero for the range.
- Allow Partial Credit: Allow partial credit on a less accurate range of answers. Set the Partial Credit Points Percentage to be awarded if the student’s answer is within the partial credit range.
- Units Required: The unit of measurement must be provided in the student’s answer. Type the Answer Units and Units Points Percentage to be awarded if the units are entered correctly.
The following two examples use variables in equations. You can see how the instructor crafted the question text and the resulting student view of the question.
Video: Creating a Calculated Formula Question (Flash video | 3m 19s)