Metrohm viva 1.0 Manual - Manual (Page 607)

￭￭￭￭￭￭￭￭￭￭￭￭￭￭￭￭￭￭￭￭￭￭
5 Method
viva 1.0
￭￭￭￭￭￭￭￭ 595
the number of measuring points and f is the number of estimated parame-
ters. The student factor t is defined as follows for a probability of 68.3%:
n − f t n − f t n − f t Curve type f
1 1.837 6 1.091 15 1.035 y = a + bx 2
2 1.321 7 1.077 20 1.026 y = a + bx + cx 2 3
3 1.197 8 1.067 30 1.017 y = a + bx + dx 4 3
4 1.142 9 1.059 50 1.010
5 1.111 10 1.053 100 1.005
Even though probabilities of 90% and more are usual in statistics, we
select 68.3% in order to ensure compatibility with the conventional speci-
fication of normally distributed measured values Mean value
± Standard
deviation. With normally distributed values, a standard deviation corre-
sponds to a probability of 68.3%.
The total error CONCM.ASD of the result CONCM consequently indi-
cates the CONCM
± CONCM.ASD area in which the true value of
CONCM may be expected with a probability of 68.3%.
5.6.7.3 Curve results
5.6.7.3.1 Substance name
Variable name RS.’Command name’.’Substance name’.VAR{x}.REP{y}.SUBST
(with call-up of the VA measuring command by CALL VA)
RS.’Command name’.’Substance name’.VMS.REP{y}.SUBST (with
call-up of the VA measuring command by CALL VMS)
RS.’Command name’.’Substance name’.INTERCEPT.REP{y}.SUBST
(with call-up of the VA measuring command by CALL INTERCEPT)
RS.’Command name’.’Substance name’.'CALL
COND'{x}.REP{y}.SUBST (with call-up of the VA measuring command
by CALL COND)
Description Substance name.
Decimal places −
Unit −
Remarks This variable can be used if the substance name is to appear in a message
(e.g. in the commands WAIT or REQUEST).