# Difference Between Accuracy And Precision Lab Report

965 Words 4 Pages
Accuracy and Precision Lab Report By Connor MacFarland

10.23.2016
IBC 1
Question
What is the difference between accuracy and precision and how can we demonstrate the difference?
MATERIALS
Pencil
Notebook Paper
1 Gallon of water
Ruler
Unmarked Plastic Container
3 different kinds of Rocks of different sizes
Triple Beam Balance
PROCEDURE
Estimating Lengths Procedure
A piece of notebook paper was torn into 8 rectangles
Without a ruler, a line was drawn which was estimated to be 5cm long on one of the rectangles
Repeated step 2 on three separate sheets of paper
Measured the length of the lines with a ruler
Repeat the above process with the remaining 4 pieces
Measure the actual lengths of the lines drawn with
Accuracy is represented by percent error. The lower the percent error the more accurate the measurement is. For Example a low percent error of 4% is accurate vs 100%. Precision is when the estimated value is not as close to the actual value, but all of the estimated values are close to each other. Precision is represented by Average Deviation. The lower the average deviation is the more precise a measurement. For example 1.1 and 1.2 is precise because they are close to each other.

EVIDENCE:
The percent error for the hand drawn lines table 1 data was precise because the average deviation was 0.625. As for data table 2 data was precise because its average deviation was 0.75. Neither data sets were accurate because the percent error for both was greater than 10%.
The second data set which measured volume was neither precise nor accurate because the percent error was greater than 10% (21%). The average Deviation was 19.75 which is not precise.

The third data set which measured mass was neither precise nor accurate because the percent error was greater than 10%(67%) The average deviation was 5.6 which is not
This may have caused the measurements to be off.
My ideas haven't changed because i've done this lab before. For future experience i have to look at the broader picture like “what will happen if this isn’t done right”. I now have an understanding on accuracy and precision on how they relate to percent error and average deviation.
LAB QUESTIONS:
Questions Hand Drawn lines
Data set 2 because the percent error was lower than Data set 1.
Data set 2 because the deviation was less than data set 1.
In this case yes but it does not have to be because of the average deviation.

Questions Estimating Volume
No because the percent error as long as it’s above 10% it’s not accurate.
Yes because I got a feel of how much to fill the unmarked plastic container
Yes because I got a feel of how much to fill the unmarked plastic container.

Questions Estimated Mass
No because the percent error as long as it’s above 10% it’s not accurate.
No because I had different masses with different trials because we had different rocks which had different masses.
No because each trial was different.
Length because I got a feel for it as we kept going through

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