EXERCISE 1. PRECISION AND ACCURACY
Objectives:
- To know the difference between precision and accuracy
- To be able to compute precision and accuracy
- To deduce possible errors in experiments
Materials: Ruler
Procedure
- Measure the length and width (cm) of the table assigned to you. Each student should have their own turns in measuring without relying or copying the data of your group mate.
- Compute the area of the table (expressed units in square centimeters). Record your data on Table 1.1
- Compute for the deviation of your AREA table using the formula
d=Ū-Ui where Ū is the AVERAGE AREA
and Ui are the INDIVIDUAL CALCULATED AREA
After you get the deviation, compute for the AVERAGE DEVIATION (AD = d1+d2+d3….+dn/n)
- Get the True Value (TV) of your table from your teacher and compute for the INDIVIDUAL PERCENT ERROR (%E)
%E = /TV-OV/ x 100
TV
Where TV = True Value
OV = Observed Value (calculated area)
- Get the % Error of the other groups and compare it with your % Error.
Data/Illustration
Table 1.1 Dimensions of the table
Student (Ui) | Length (cm) | Width (cm) | Area (sq cm) |
Table 1.2 Deviations and Percentage Error within the Group
Student (Ui) | Deviation (d) | Ave. Dev (AD) | % Error (% E) | Ave % E (APE) |
Table 1.3 APE of Other Groups
Group Number | APE |
Guide Questions for Discussions
- What is precision? What is accuracy?
- What is the difference between precision and accuracy?
- What is the basis if your measurements are precise? If your measurements are accurate?
- Which student within your group has the most precise measurement? Has the most accurate? Why?
- Which group has the most accurate measurements and why?
- Site some possible errors encountered or committed in the experiments? How will you work out on these errors?
- Which is more important in measurements; precision or accuracy? Why?
*Deadline for Submission of Lab Reports will be on TUE 5pm (for MWF Natsci Class)
And Mon 5 pm (for TTH Natsci Class)
Rlp2011
