Question

A length measurement is 1.40 cm. The correct value is 1.36 cm. Calculate the percent
error.

Answer 1

2.94%

Step-by-step explanation:

Percent error is a measurement of the accuracy of an observed value.

Finding Percent Error

The formula for percent error is
`|(E-A)/(A) |*100`, where E is the experimental value and A is the actual value. We take the absolute value because the percent error is always positive, and we multiply by 100 at the end to go from decimal to percentage. In this case, the experimental value is 1.40 cm and the actual value is 1.36 cm.

So, we can plug our values in to solve.

• 
  `|(1.40-1.36)/(1.36) |` = 0.0294

Then, multiply by 100 to get a 2.94% error.

Interpreting Percent Error

The smaller the percent error, the closer you were to the actual value. So, a percent error of 2.94% shows that the measurement was accurate. Oftentimes, a percent error of below 5% is considered accurate. Although, it's important to understand that different experiments will have different expectations for percent error. Human error or instrument error can both contribute to higher percent errors.