/usr/include/dlib/statistics/ is in libdlib-dev 18.18-1.
This file is owned by root:root, with mode 0o755.
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/usr/include/dlib/statistics/average_precision.h
/usr/include/dlib/statistics/average_precision_abstract.h
/usr/include/dlib/statistics/cca.h
/usr/include/dlib/statistics/cca_abstract.h
/usr/include/dlib/statistics/dpca.h
/usr/include/dlib/statistics/dpca_abstract.h
/usr/include/dlib/statistics/image_feature_sampling.h
/usr/include/dlib/statistics/image_feature_sampling_abstract.h
/usr/include/dlib/statistics/lda.h
/usr/include/dlib/statistics/lda_abstract.h
/usr/include/dlib/statistics/random_subset_selector.h
/usr/include/dlib/statistics/random_subset_selector_abstract.h
/usr/include/dlib/statistics/sammon.h
/usr/include/dlib/statistics/sammon_abstract.h
/usr/include/dlib/statistics/statistics.h
/usr/include/dlib/statistics/statistics_abstract.h
/usr/include/dlib/statistics/vector_normalizer_frobmetric.h
/usr/include/dlib/statistics/vector_normalizer_frobmetric_abstract.h