Percent Error in Estimations
Percent Error
The percent that an
estimate varies from
an actual amount
Vocabulary
•
The
percent error is
:
–
a ratio that compares the inaccuracy of an
estimate, or the
amount of error,
to the
actual amount.
•
To find the
percent error
, the proportion used is:
Ex 1) As a fundraiser, the Student Activities
Council sold chances to guess the number of jelly
beans in a jar. Brenda won the raffle with a guess
of 370 jelly beans even though there were actually
400 jelly beans in the jar. What was the
percent
error
?
Subtract the guess and the actual
value to find the amount of error.
The percent error between Brenda’s guess
and the actual amount is 7.5%.
Ex 2) George is adding a rail around his
back porch, and he estimates that the
length of the porch is 13.5 feet. The actual
length is 15 feet. Find the
percent error
in George’s estimate.
Subtract the estimate and the
actual value to find the amount
of error.
The percent error between George’s
estimate and the actual amount is 10%.
Ex 3) The odometer in Mr. Washington’s car does not work
correctly. The odometer recorded 26.4 miles for his last trip to
the hardware store, but he knows the distance traveled is 30 miles.
What is the percent error?
The percent error
between the car’s
odometer and the
actual distance was
12%.
Subtract the
odometer’s
mileage from
the actual
distance to
find the
amount of
error.
Ex 4) The exact value for the density of aluminum is 2.699 g/cm³.
Working in the science lab at school, Joseph finds the density of a
piece of aluminum to be 2.75 g/cm³. What is Joseph’s percent
error?
Round your answer to the nearest hundredth.
The percent error between Joseph’s findings
and aluminum’s actual density was 1.89%.
Subtract Joseph’s
calculated density
from the actual
density find the
amount of error.
Percent error is a measure that compares the accuracy of an estimate to the actual value, expressed as a percentage. By calculating the difference between the estimate and actual amount, you can find the percent error. With examples ranging from estimating jelly beans in a jar to measuring the density of a substance, this concept is explained with practical scenarios. Learn how to determine percent error and apply it in various real-life situations.
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Presentation Transcript
Percent Error The percent that an estimate varies from an actual amount
Vocabulary The percent error is: a ratio that compares the inaccuracy of an estimate, or the amount of error, to the actual amount. To find the percent error, the proportion used is: percent error amount of error = 100 actual amount
Ex 1) As a fundraiser, the Student Activities Council sold chances to guess the number of jelly beans in a jar. Brenda won the raffle with a guess of 370 jelly beans even though there were actually 400 jelly beans in the jar. What was the percent error? percent error amount of error = 100 actual amount 400 370 x Subtract the guess and the actual value to find the amount of error. = 100 x 400 30 = 100 400 = 400 3000 x = 5 . 7 % x The percent error between Brenda s guess and the actual amount is 7.5%.
Ex 2) George is adding a rail around his back porch, and he estimates that the length of the porch is 13.5 feet. The actual length is 15 feet. Find the percent error in George s estimate. percent error amount of error = 100 actual amount 15 13 5 . x Subtract the estimate and the actual value to find the amount of error. = 100 15 The percent error between George s estimate and the actual amount is 10%.
Ex 3) The odometer in Mr. Washingtons car does not work correctly. The odometer recorded 26.4 miles for his last trip to the hardware store, but he knows the distance traveled is 30 miles. What is the percent error? Subtract the odometer s mileage from the actual distance to find the amount of error. The percent error between the car s odometer and the actual distance was 12%.
Ex 4) The exact value for the density of aluminum is 2.699 g/cm. Working in the science lab at school, Joseph finds the density of a piece of aluminum to be 2.75 g/cm . What is Joseph s percent error? Round your answer to the nearest hundredth. Subtract Joseph s calculated density from the actual density find the amount of error. The percent error between Joseph s findings and aluminum s actual density was 1.89%.
