OHAUS Explorer Balances - Repeatability Worksheet

CHAPTER 4 - TESTING
Ohaus Corporation www.ohaus.com 48 Explorer
®
Series Service Manual
TABLE 4-2: REPEATABILITY WORKSHEET
n
Reading
Delta = Reading – Mean
Delta x Delta
1
2
3
4
5
6
7
8
9
10
n = number of Reading
Mean = Sum of readings / 10
Delta = Reading – Mean
Standard Deviation = Square Root of (sum of (Delta x Delta) / 9)
5. Add the ten readings and divide the total by 10 to find the Mean (average).
Mean = (Reading 1 + Reading 2 + Reading 3 + Reading 4 + Reading 5+ Reading 6 + Reading
7+ Reading 8 + Reading 9 + Reading 10) / 10
Mean =________
6. Calculate the Delta for each reading and record in the work sheet.
Delta = Reading – Mean
7. Calculate the Delta x Delta for each reading and record in worksheet.
8. Add the ten Delta x Delta values and divide by 9
9. Calculate the Standard Deviation by applying the square root of the result from step 8.
Standard Deviation =___________
Note: If the balance does not meet specifications, check environmental conditions, ensure that
the balance is level, and try again. If it still does not meet specifications, perform a service
calibration, and try again. (See Appendix B for Service Calibration)