Capintec CAPTUS 600 - Chi-Square Test; Auto Calibration Test

CAPINTEC, INC. CAPTUS
®
600
CHI-SQUARE TEST
After the printout (or screen display) of the previous section is complete, you will be asked if
you want to perform a Chi-Square Test. If so, DO NOT REMOVE THE Cs137 STANDARD,
and press Y. The Chi-Square Test will be performed using the parameters entered in
CHAPTER 5: SYSTEM INITIALIZATION, SECTION: CHI-SQUARE TEST SETUP.
The report displays the counts for each repetition and then the calculated Chi-Square.
The Chi-Square is calculated from the following equation:
()
tsmeasuremenn for the average =
it measuremenfor counts = where
1
1
2
2
x
x
xx
x
i
n
i
i
∑
=
−= χ
Chi-Square values are given in the following table for 10, 15 and 20 measurements. The Chi-
Square value should fall between the 0.95 and 0.05 probability values in the table almost all
of the time. The more stringent 0.90 and 0.10 values are given for reference.
n = # of
measurements
0.95 0.90 0.10 0.05
10 3.33 4.17 14.7 16.9
15 6.57 7.79 21.1 23.7
20 10.1 11.7 27.2 30.1
Table 6-1
If the Chi-Square falls outside of this range, first repeat the test making sure that the
background and positioning are kept constant.
If the values are still out of range, contact Capintec’s Authorized Service Center for
assistance.
You always have the option of performing the Autocalibration Test, even when the Test
shows that calibration is within established limits.
AUTO CALIBRATION TEST
When the Test procedure indicates that the CAPTUS
®
600 needs to be calibrated, you must
perform the AutoCal function.
November 07 ACCEPTANCE & QUALITY ASSURANCE TESTS 6-5