Opened 6 years ago

Closed 6 years ago

#7402 closed Bugs (fixed)

Typo in math example

Reported by: n.g.davies@… Owned by: Paul A. Bristow
Milestone: To Be Determined Component: math
Version: Boost 1.52.0 Severity: Problem
Keywords: math students t two sample Cc:

Description

In the function two_samples_t_test_equal_sd in libs/math/example/students_t_two_samples.cpp:

   //
   // Now we can calculate and output some stats:
   //
   // Degrees of freedom:
   double v = Sn1 + Sn2 - 2;
   cout << setw(55) << left << "Degrees of Freedom" << "=  " << v << "\n";
   // Pooled variance:
   double sp = sqrt(((Sn1-1) * Sd1 * Sd1 + (Sn2-1) * Sd2 * Sd2) / v);
/********* THIS LINE BELOW **********/
   cout << setw(55) << left << "Pooled Standard Deviation" << "=  " << v << "\n";
   // t-statistic:
   double t_stat = (Sm1 - Sm2) / (sp * sqrt(1.0 / Sn1 + 1.0 / Sn2));
   cout << setw(55) << left << "T Statistic" << "=  " << t_stat << "\n";

I believe the line marked should have sp in place of v.

Change History (2)

comment:1 Changed 6 years ago by John Maddock

Owner: changed from John Maddock to Paul A. Bristow

comment:2 Changed 6 years ago by Paul A. Bristow

Keywords: math students t two sample added
Resolution: fixed
Status: newclosed

Thanks for reporting this. Glad to see someone is reading this.

Corrected in trunk SVN 80706

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