Answer: -2.6%
Explanation:
Percent error is the difference between the measured and known value, and then we divide by the known value, and then multiply by 100%.
Estimated.number = 15.4 grams.
Actual number = 15.8 grams
Percentage error = (Estimated number - Actual number)/Actual number × 100
= (15.4 - 15.8)/15.8 × 100
= -0.4/15.8 × 100
= 0.0253 × 100
= 2.53
= -2.6% approximately