StudentT
StudentT (Prob, DegFree)
warning
This function is deprecated. New code should use the more accurate StatsInvStudentCDF.
The StudentT function returns the t value corresponding to an area Prob under the Student's T distribution from -t to t for DegFree degrees of freedom.
Note that this is a "bi-tail" result, which is what is usually desired. Tabulated values of the Student's T distribution are commonly the one-sided result.
StudentT calculates confidence intervals from standard deviations for normally-distributed statistics. For instance, you can use it to calculate a confidence interval for the coefficients from a curve fit:
Make/O/N=20 Data=0.5*x+2+gnoise(1) // line with Gaussian noise
Display Data
CurveFit line Data /D
Print "intercept = ", W_coef[0], "±", W_sigma[0]*StudentT(0.95, V_npnts-2)
Print "slope = ", W_coef[1], "±", W_sigma[1]*StudentT(0.95, V_npnts-2)