CHAPTER 4 TESTING
Ohaus Corporation www.ohaus.com
4-4
Ranger
™
(Count) 3000 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).
6. Mean = (Reading 1 + Reading 2 + Reading 3 + Reading 4 + Reading 5
7. + 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, move it to a suitable location, ensure
that it is level, and try again.
