How is the percentage error calculated?

The correct method for calculating percentage error involves determining the difference between the actual and expected values, dividing that difference by the expected value, and then multiplying by 100 to convert it to a percentage. The formula used is:

|(actual - expected)/expected| x 100.

This approach provides a measure of how far off an actual measurement is from a theoretical or expected value in relative terms.

The absolute value is taken to ensure that the result is non-negative, which allows for comparisons regardless of whether the actual value is above or below the expected value. By dividing by the expected value, the calculation gives context to the difference, making it relative to the magnitude of the expected value.

Overall, this method effectively communicates how significant an error is, as it accounts for both the size of the difference and the size of the expected value, resulting in a meaningful measure of error in practical applications, especially important in fields like medical imaging.