1. What is Percentage Deviation?

Percentage Deviation (PD) measures how much an actual value differs from an expected value, expressed as a percentage of the expected value. It's commonly used in statistics, quality control, and experimental sciences.

2. How Does the Calculator Work?

The calculator uses the Percentage Deviation formula:

Where:

• \( actual \) — The observed or measured value
• \( expected \) — The theoretical or desired value

Explanation: The absolute difference between actual and expected is divided by the expected value and multiplied by 100 to get a percentage.

3. Importance of Percentage Deviation

Details: Percentage deviation is crucial for quality assessment, experimental validation, and process control. It helps quantify how close measurements are to expected values.

4. Using the Calculator

Tips: Enter both actual and expected values. The expected value cannot be zero (division by zero is undefined). Values can be positive or negative.

5. Frequently Asked Questions (FAQ)

Q1: What's a good percentage deviation?
A: This depends on the context. In some fields <5% is excellent, while others may tolerate up to 20%.

Q2: How is this different from percent error?
A: They're essentially the same when comparing experimental to theoretical values. Some fields use different terms.

Q3: Can percentage deviation be negative?
A: No, because we use absolute value in the numerator. The direction of deviation isn't indicated.

Q4: What if my expected value is zero?
A: The calculation becomes undefined. Consider using absolute difference instead in such cases.

Q5: How precise should my result be?
A: Typically 1-2 decimal places are sufficient for percentage deviation reporting.