BatchKi Reference Manual

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[Confidence Intervals]

This section of the default settings file controls the computation of confidence intervals for the inhibition constant. The default values are shown below.

[Confidence Intervals]
  Exact = yes
  FixedEnzyme = yes
  Level = 99

Parameter Exact

If the parameter Exact is set to `no', the program will compute the approximate confidence intervals for best-fit values of inhibition constants using equation 4.1

$$K^{*}_{\pm} = K^{*} \pm s_K \times t \,(n - m, \alpha/2) \quad ,$$ (4.1)

where $t(n-m, \alpha/2)$ is the Student t-statistic at $\alpha/2$ probability level with $n-m$ degrees of freedom ([3], p. 6, equation 1.12). For more details, see the discussion later in this document in section 6.1.2.

If the parameter Exact is set to `yes', the program will compute confidence intervals for model parameters using the profile-t method of Bates and Watts ([3], p. 302). Again, for more details see section 6.1.2.

Parameter FixedEnzyme

This parameter is relevant only if the confidence interval estimation is performed by using the Bates & Watts method (Exact = yes, ref. [3], p. 302).

If FixedEnzyme is set to `yes', which is the recommended value, the program will treat the enzyme concentration as a fixed parameter regardless of how it was treated in the preceding least-squares fit.

If FixedEnzyme is set to `no', then during the confidence interval search the enzyme concentration is treated either as a constant, or as an adjustable parameter, depending on how it was treated in the preceding least-squares fit (see section 4.2.1 for details).

Parameter Level

Whether the confidence intervals for inhibition constants are determined by the very approximate method using a simple multiple of the standard error (Exact = no), or by the more rigorous method using the profile-t method (Exact = yes), in either case the probability level is set by the parameter Level. This parameter is expressed as percentage points. The most frequently used probability level is 95% (Level = 95), although we recommend the confidence level 99%.

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Petr Kuzmic | Jul 12 2008