Lauren decided to see how many jumping jakes she could do in 10 seconds. she told her mom that she could do 20. she was acually able to complete 15 jumping jacks when the timer went off. what was her percent error.

Her error was overestimating by 33.3%  

Step-by-step explanation:

To calculate a relative error (or percent error), we need to identify the absolute error first. In this case, the absolute error is the difference between Lauren's estimate and the actual outcome: 15 jacks - 20 estimated jacks = -5. The fact that this error is negative is only to indicate that Lauren overestimated (as opposed to underestimated). Usually, the absolute value is taken.

As next step, the absolute error is made to a relative one by dividing by the ground truth, which is the actual outcome of 15 jumping jacks. The relative error = |-5|/15 = 1/3. Expressed in percent: 33.3%. Lauren made an error of 33.3% (overestimate).