In a laboratory, a student finds the boiling point of water at sea level to be 102.0 °C. The true value of the boiling point of water at sea level is 100.0 °C. What is the student's
percent error?

One reason, that water did not boil at 100 C could be the atmospheric pressure

Calculate the percent error for each sample from the theoretical 100°c

Percent error ( 102C) = (102-100/ 100) *100

= 2% error

the answer is 75.0%.