Bio-Tek ELx800, Руководство оператора

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Chapter 3: Operation
C U R V E - F I T T Y P E : C - S P L I N E
C - S P L I N E P T - P T * M O R E
• Linear curve fit: A simple best-fit straight line is plotted using the
values of the standards.
•
Quadratic or “Quad” curve fit: A curve fit that uses the quadratic
equation “ax
2
+bx +c = y” to plot the standard’s values. Utilizing this
curve, any data point for a standard that deviates from the ideal value
will not affect the entire curve.
• Cubic curve fit: A curve fit that uses the equation
“ax
3
+ bx
2
+ cx + d = y” to plot the standard’s values. This type of curve
fit is affected even less than the quadratic fit when any particular
standard has a poor value.
•
2-P (LOGIT/LOG): A curve fitted to the standard values, which is
characterized by a skewed sigmoidal (S-shaped) plot that eventually
becomes asymptotic to the upper and lower standard values. The
logistic equation is algebraically transformed to a simpler form in which
experimentally determined values are used for the responses at
concentrations of zero and infinity.
Note: Uses linear axis type only.
•
Cubic Spline (C-Spline) curve fit: A piecewise polynomial
approximation consisting of joining a set of data points by a series of
straight lines, which is then smoothed by using a cubic fit.
• 4-Parameter Logistic or “4-P”: A curve fitted to the standard values,
which is characterized by a skewed sigmoidal (S-shaped) plot that
becomes asymptotic to the upper and lower standard values. The 4
parameters are: Left asymptote, Right asymptote, Slope and Value at
the Inflection point. This fit is most recommended for immunoassay
data, and is more exact than Logit/Log.
Note: Uses linear axis type
only.
• Point to Point or “PT to PT”: A plot that connects each standard point
with a line, with no averaging of the values to “smooth” the curve at
each standard.
•
Press SOFT KEYS 1, 2, 3, or 4 to select the curve-fit type that is
displayed above the soft key. Select
*MORE
to display additional
options.
•
Press ENTER to save the selection and advance to the next screen.
Bio-Tek Instruments, Inc.