 6.13 Tutorial: Setting Margin of Tolerance in Non-numeric Questions - Maple T.A. 2016 Help # Maple T.A. Online Help

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## 6.13 Tutorial: Setting Margin of Tolerance in Non-numeric Questions

 Note: Use the Question Editor on-screen dialog boxes for setting the margin of error in numeric and numeric-with-unit questions. For more information, see Setting the Answer Format in Numeric Questions.

For an introduction to the concept of margin of error, see Controlling Answer Tolerance.

For basic information on the system plus or minus operator, "?", see Setting a Margin of Error in Non-numeric Questions.

### Absolute Errors

You can specify an absolute error using the ? operator.

x ? y represents x +/- y.

#### Example 1

`2.12 ? 0.01 `

specifies a margin of error of +/- 0.01 in the answer. The answer matches any response between 2.11 and 2.13 (inclusive). For example, the system grades 2.114 or 2.123456789, as well as 2.11 and 2.13, correct.

#### Example 2

`2.1J ? 0.25J `

specifies a margin of error of +/- 0.25J. The system grades correct any response between 1.85J and 2.35J. The error must have the same dimension as the correct answer.

#### Example 3

`cos(pi/6) ? 1000 `

specifies a margin of error of +/- 1000. The system grades correct any response between cos(pi/6)-1000 and cos(pi/6)+1000, approximately between -999.1339746 and 1000.866025.

### Percentage Errors

You can also specify a percentage error using the ? operator.

x (1 ? y) represents x +/- x*y.

#### Example 4

`1.52 (1 ? 0.025)`

specifies a margin of error of 2.5%. The system grades correct any response between 1.444 and 1.596.

#### Example 5

`50 (1 ? 1.1)`

specifies a margin of error of 110%. The system grades correct any response between -5 and 105.

### Algorithmic Variables

You can use a margin of error with answers that are algorithmic variables. Consider a question in which the correct answer is assigned to \$answer.

 Note: The ? operator cannot be used in an algorithmic variable definition (or other algorithmic statement).

Example 6

To specify an absolute margin of error of 0.1, use:

```\$answer ? 0.1
```

#### Example 7

To specify a percentage margin of error of 3%, use:

`\$answer (1 ? 0.03)`

### Using the ? Operator in Complex Expressions

You can use the ? operator in complex expressions. It is an arithmetic operator.

Example 8

`2.12?0.01 `

matches any response between 2.11 and 2.13 and

`2*(2.12?0.01) `

matches any response between 4.22 and 4.26.

Example 9

The ordinary rules of arithmetic (for example, the distributive rule) apply.

`2*(2.12?0.01) `

is equivalent to:

`(2*2.12)?(2*0.01) `

Example 10

You can specify very complicated ranges of numbers.

`((2.17 ? 0.01) + e^(1.07?2.03))/(1? 0.5)`

 Important: If the exact answer is an expression, not a simple formula, number, or variable, ensure that you use parentheses to generate the correct answer.

#### Example 11

`2 + 2 * (1 ? 0.05) `

which defines a tolerance of 5% of 2, is different from:

`(2 + 2) * (1 ? 0.05) `

which defines a tolerance of 5% of the sum 4.

See Also:

Controlling Answer Tolerance