diff --git a/apps/probability/test/distributions.cpp b/apps/probability/test/distributions.cpp
index a1a46b13c..13ef18a9d 100644
--- a/apps/probability/test/distributions.cpp
+++ b/apps/probability/test/distributions.cpp
@@ -12,12 +12,12 @@ void assert_cumulative_distributive_function_direct_and_inverse_is(Probability::
   double r = distribution->cumulativeDistributiveFunctionAtAbscissa(x);
   quiz_assert(!std::isnan(r));
   quiz_assert(!std::isinf(r));
-  quiz_assert(std::abs(r-result) < FLT_EPSILON || std::abs(r-result)/result < FLT_EPSILON);
+  quiz_assert(std::fabs(r-result) < FLT_EPSILON || std::fabs(r-result)/result < FLT_EPSILON);
 
   r = distribution->cumulativeDistributiveInverseForProbability(&result);
   quiz_assert(!std::isnan(r));
   quiz_assert(!std::isinf(r));
-  quiz_assert(std::abs(r-x) < FLT_EPSILON || std::abs(r-x)/x < FLT_EPSILON);
+  quiz_assert(std::fabs(r-x) < FLT_EPSILON || std::fabs(r-x)/x < FLT_EPSILON);
 
 }
 
diff --git a/apps/probability/test/hypergeometric_function.cpp b/apps/probability/test/hypergeometric_function.cpp
index 771e6e7d1..0669aa839 100644
--- a/apps/probability/test/hypergeometric_function.cpp
+++ b/apps/probability/test/hypergeometric_function.cpp
@@ -10,7 +10,7 @@ void assert_hypergeometric_is(double a, double b, double c, double z, double res
   double r = 0.0;
   const double precision = FLT_EPSILON;
   quiz_assert(hypergeometricFunction(a, b, c, z, precision, 1000, &r));
-  quiz_assert(std::abs(r - result)/result <= 100 * precision); // Multiply by 100 because precision is too strict
+  quiz_assert(std::fabs(r - result)/result <= 100 * precision); // Multiply by 100 because precision is too strict
 }
 
 QUIZ_CASE(hypergeometric_function) {
diff --git a/apps/probability/test/regularized_gamma.cpp b/apps/probability/test/regularized_gamma.cpp
index 19794e5d9..d70217590 100644
--- a/apps/probability/test/regularized_gamma.cpp
+++ b/apps/probability/test/regularized_gamma.cpp
@@ -10,7 +10,7 @@ void assert_regularized_gamma_is(double s, double x, double result) {
   double r = 0.0;
   const double precision = FLT_EPSILON;
   regularizedGamma(s, x, precision, Probability::ChiSquaredDistribution::k_maxRegularizedGammaIterations, &r);
-  quiz_assert(std::abs(r - result) <= precision);
+  quiz_assert(std::fabs(r - result) <= precision);
 }
 
 QUIZ_CASE(regularized_gamma) {