Capintec CAPTUS 3000 User Manual

CAPINTEC, INC. CAPTUS
®
3000
CHI-SQUARE TEST
CAUTION: Calibration is recommended before making any measurements. Refer to
the AUTO CALIBRATION section on page 5-5.
The Chi-Square Test provides a sensitive check of the overall counting performance of the
system. The software will use the 662 keV peak of your Cs137 source for the tests.
# Repetitions 0.95 0.90 0.10 0.05
5
.711
1.06
7.78
9.49
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
In the table above, you can see that for a typical 10-repetition test, the Chi-Square value
should be between 3.33 and 16.9 for 95% of the time. Therefore, it is expected to be outside
this range 5% of the time. Also, because of the statistical nature of the Chi-Squared test, the
Chi-Square values should not remain exactly the same. They are expected to vary.
The Chi-Squared test value is calculated from the following equation:
( )
∑
=
−=
n
i
avi
av
xx
x
1
2
2
1
χ
tsmeasuremen for the average
t measuremenfor counts where
nx
ix
av
i
=
=
This equation is the same as the following:
( ) ( ) ( ) { }
22
2
2
1
2
...
1
avnavav
av
xxxxxx
x
−++−+−= χ
1. Click the button or press Alt+H on Figure 5-1 Quality Assurance
Main Screen. The screen appears as shown in Figure 5-16 Chi-Square Test Screen.
July 14 QUALITY ASSURANCE 5-15

Capintec CAPTUS 3000 Specifications

General

Brand	Capintec
Model	CAPTUS 3000
Category	Medical Equipment
Language	English