Perfeito, consegui instalar o numpy.
No entanto, ainda estou tendo problemas - dessa vez, para instalar o scipy. 
c:\Python27\Scripts
λ pip install scipy
Collecting scipy
  Downloading scipy-0.18.1.tar.gz (13.1MB)
    100% |################################| 13.1MB 48kB/s
Installing collected packages: scipy
  Running setup.py install for scipy ... error
    Complete output from command c:\python27\python.exe -u -c "import setuptools, tokenize;__file__='c:\\users\\arthur~1\\appdata\\local\\temp\\pip-build-r9tji9\\scipy\\setup.py';exec(compile(getattr(tokenize, 'open', open)(__file__).read().replace('\r\n', '\n'), __file__, 'exec'))" install --record c:\users\arthur~1\appdata\local\temp\pip-ussxqz-record\install-record.txt --single-version-externally-managed --compile:
    Note: if you need reliable uninstall behavior, then install
    with pip instead of using `setup.py install`:
      - `pip install .`       (from a git repo or downloaded source
                               release)
      - `pip install scipy`   (last SciPy release on PyPI)
    lapack_opt_info:
    openblas_lapack_info:
      libraries openblas not found in ['c:\\python27\\lib', 'C:\\', 'c:\\python27\\libs']
      NOT AVAILABLE
    lapack_mkl_info:
      libraries mkl_rt not found in ['c:\\python27\\lib', 'C:\\', 'c:\\python27\\libs']
      NOT AVAILABLE
    atlas_3_10_threads_info:
    Setting PTATLAS=ATLAS
    c:\python27\lib\site-packages\numpy\distutils\system_info.py:639: UserWarning: Specified path C:\projects\numpy-wheels\windows-wheel-builder\atlas-builds\atlas-3.10.1-sse2-32\lib is invalid.
      warnings.warn('Specified path %s is invalid.' % d)
    <class 'numpy.distutils.system_info.atlas_3_10_threads_info'>
      NOT AVAILABLE
    atlas_3_10_info:
    <class 'numpy.distutils.system_info.atlas_3_10_info'>
      NOT AVAILABLE
    atlas_threads_info:
    Setting PTATLAS=ATLAS
    <class 'numpy.distutils.system_info.atlas_threads_info'>
      NOT AVAILABLE
    atlas_info:
    <class 'numpy.distutils.system_info.atlas_info'>
      NOT AVAILABLE
    c:\python27\lib\site-packages\numpy\distutils\system_info.py:1532: UserWarning:
        Atlas (http://math-atlas.sourceforge.net/) libraries not found.
        Directories to search for the libraries can be specified in the
        numpy/distutils/site.cfg file (section [atlas]) or by setting
        the ATLAS environment variable.
      warnings.warn(AtlasNotFoundError.__doc__)
    lapack_info:
      libraries lapack not found in ['c:\\python27\\lib', 'C:\\', 'c:\\python27\\libs']
      NOT AVAILABLE
    c:\python27\lib\site-packages\numpy\distutils\system_info.py:1543: UserWarning:
        Lapack (http://www.netlib.org/lapack/) libraries not found.
        Directories to search for the libraries can be specified in the
        numpy/distutils/site.cfg file (section [lapack]) or by setting
        the LAPACK environment variable.
      warnings.warn(LapackNotFoundError.__doc__)
    lapack_src_info:
      NOT AVAILABLE
    c:\python27\lib\site-packages\numpy\distutils\system_info.py:1546: UserWarning:
        Lapack (http://www.netlib.org/lapack/) sources not found.
        Directories to search for the sources can be specified in the
        numpy/distutils/site.cfg file (section [lapack_src]) or by setting
        the LAPACK_SRC environment variable.
      warnings.warn(LapackSrcNotFoundError.__doc__)
      NOT AVAILABLE
    Running from scipy source directory.
    Traceback (most recent call last):
      File "<string>", line 1, in <module>
      File "c:\users\arthur~1\appdata\local\temp\pip-build-r9tji9\scipy\setup.py", line 415, in <module>
        setup_package()
      File "c:\users\arthur~1\appdata\local\temp\pip-build-r9tji9\scipy\setup.py", line 411, in setup_package
        setup(**metadata)
      File "c:\python27\lib\site-packages\numpy\distutils\core.py", line 135, in setup
        config = configuration()
      File "c:\users\arthur~1\appdata\local\temp\pip-build-r9tji9\scipy\setup.py", line 335, in configuration
        config.add_subpackage('scipy')
      File "c:\python27\lib\site-packages\numpy\distutils\misc_util.py", line 1000, in add_subpackage
        caller_level = 2)
      File "c:\python27\lib\site-packages\numpy\distutils\misc_util.py", line 969, in get_subpackage
        caller_level = caller_level + 1)
      File "c:\python27\lib\site-packages\numpy\distutils\misc_util.py", line 906, in _get_configuration_from_setup_py
        config = setup_module.configuration(*args)
      File "scipy\setup.py", line 15, in configuration
        config.add_subpackage('linalg')
      File "c:\python27\lib\site-packages\numpy\distutils\misc_util.py", line 1000, in add_subpackage
        caller_level = 2)
      File "c:\python27\lib\site-packages\numpy\distutils\misc_util.py", line 969, in get_subpackage
        caller_level = caller_level + 1)
      File "c:\python27\lib\site-packages\numpy\distutils\misc_util.py", line 906, in _get_configuration_from_setup_py
        config = setup_module.configuration(*args)
      File "scipy\linalg\setup.py", line 20, in configuration
        raise NotFoundError('no lapack/blas resources found')
    numpy.distutils.system_info.NotFoundError: no lapack/blas resources found
    ----------------------------------------
Command "c:\python27\python.exe -u -c "import setuptools, tokenize;__file__='c:\\users\\arthur~1\\appdata\\local\\temp\\pip-build-r9tji9\\scipy\\setup.py';exec(compile(getattr(tokenize, 'open', open)(__file__).read().replace('\r\n', '\n'), __file__, 'exec'))" install --record c:\users\arthur~1\appdata\local\temp\pip-ussxqz-record\install-record.txt --single-version-externally-managed --compile" failed with error code 1 in c:\users\arthur~1\appdata\local\temp\pip-build-r9tji9\scipy\
You are using pip version 8.1.1, however version 9.0.1 is available.
You should consider upgrading via the 'python -m pip install --upgrade pip' command.
Tentei desinstalá-lo, mas tive uma resposta semelhante
c:\Python27\Scripts
λ pip install -U scipy
Collecting scipy
  Using cached scipy-0.18.1.tar.gz
Installing collected packages: scipy
  Running setup.py install for scipy ... error
    Complete output from command c:\python27\python.exe -u -c "import setuptools, tokenize;__file__='c:\\users\\arthur~1\\appdata\\local\\temp\\pip-build-v1zg6s\\scipy\\setup.py';exec(compile(getattr(tokenize, 'open', open)(__file__).read().replace('\r\n', '\n'), __file__, 'exec'))" install --record c:\users\arthur~1\appdata\local\temp\pip-fcvwft-record\install-record.txt --single-version-externally-managed --compile:
    Note: if you need reliable uninstall behavior, then install
    with pip instead of using `setup.py install`:
      - `pip install .`       (from a git repo or downloaded source
                               release)
      - `pip install scipy`   (last SciPy release on PyPI)
    lapack_opt_info:
    openblas_lapack_info:
      libraries openblas not found in ['c:\\python27\\lib', 'C:\\', 'c:\\python27\\libs']
      NOT AVAILABLE
    lapack_mkl_info:
      libraries mkl_rt not found in ['c:\\python27\\lib', 'C:\\', 'c:\\python27\\libs']
      NOT AVAILABLE
    atlas_3_10_threads_info:
    Setting PTATLAS=ATLAS
    c:\python27\lib\site-packages\numpy\distutils\system_info.py:639: UserWarning: Specified path C:\projects\numpy-wheels\windows-wheel-builder\atlas-builds\atlas-3.10.1-sse2-32\lib is invalid.
      warnings.warn('Specified path %s is invalid.' % d)
    <class 'numpy.distutils.system_info.atlas_3_10_threads_info'>
      NOT AVAILABLE
    atlas_3_10_info:
    <class 'numpy.distutils.system_info.atlas_3_10_info'>
      NOT AVAILABLE
    atlas_threads_info:
    Setting PTATLAS=ATLAS
    <class 'numpy.distutils.system_info.atlas_threads_info'>
      NOT AVAILABLE
    atlas_info:
    <class 'numpy.distutils.system_info.atlas_info'>
      NOT AVAILABLE
    c:\python27\lib\site-packages\numpy\distutils\system_info.py:1532: UserWarning:
        Atlas (http://math-atlas.sourceforge.net/) libraries not found.
        Directories to search for the libraries can be specified in the
        numpy/distutils/site.cfg file (section [atlas]) or by setting
        the ATLAS environment variable.
      warnings.warn(AtlasNotFoundError.__doc__)
    lapack_info:
      libraries lapack not found in ['c:\\python27\\lib', 'C:\\', 'c:\\python27\\libs']
      NOT AVAILABLE
    c:\python27\lib\site-packages\numpy\distutils\system_info.py:1543: UserWarning:
        Lapack (http://www.netlib.org/lapack/) libraries not found.
        Directories to search for the libraries can be specified in the
        numpy/distutils/site.cfg file (section [lapack]) or by setting
        the LAPACK environment variable.
      warnings.warn(LapackNotFoundError.__doc__)
    lapack_src_info:
      NOT AVAILABLE
    c:\python27\lib\site-packages\numpy\distutils\system_info.py:1546: UserWarning:
        Lapack (http://www.netlib.org/lapack/) sources not found.
        Directories to search for the sources can be specified in the
        numpy/distutils/site.cfg file (section [lapack_src]) or by setting
        the LAPACK_SRC environment variable.
      warnings.warn(LapackSrcNotFoundError.__doc__)
      NOT AVAILABLE
    Running from scipy source directory.
    Traceback (most recent call last):
      File "<string>", line 1, in <module>
      File "c:\users\arthur~1\appdata\local\temp\pip-build-v1zg6s\scipy\setup.py", line 415, in <module>
        setup_package()
      File "c:\users\arthur~1\appdata\local\temp\pip-build-v1zg6s\scipy\setup.py", line 411, in setup_package
        setup(**metadata)
      File "c:\python27\lib\site-packages\numpy\distutils\core.py", line 135, in setup
        config = configuration()
      File "c:\users\arthur~1\appdata\local\temp\pip-build-v1zg6s\scipy\setup.py", line 335, in configuration
        config.add_subpackage('scipy')
      File "c:\python27\lib\site-packages\numpy\distutils\misc_util.py", line 1000, in add_subpackage
        caller_level = 2)
      File "c:\python27\lib\site-packages\numpy\distutils\misc_util.py", line 969, in get_subpackage
        caller_level = caller_level + 1)
      File "c:\python27\lib\site-packages\numpy\distutils\misc_util.py", line 906, in _get_configuration_from_setup_py
        config = setup_module.configuration(*args)
      File "scipy\setup.py", line 15, in configuration
        config.add_subpackage('linalg')
      File "c:\python27\lib\site-packages\numpy\distutils\misc_util.py", line 1000, in add_subpackage
        caller_level = 2)
      File "c:\python27\lib\site-packages\numpy\distutils\misc_util.py", line 969, in get_subpackage
        caller_level = caller_level + 1)
      File "c:\python27\lib\site-packages\numpy\distutils\misc_util.py", line 906, in _get_configuration_from_setup_py
        config = setup_module.configuration(*args)
      File "scipy\linalg\setup.py", line 20, in configuration
        raise NotFoundError('no lapack/blas resources found')
    numpy.distutils.system_info.NotFoundError: no lapack/blas resources found
    ----------------------------------------
Command "c:\python27\python.exe -u -c "import setuptools, tokenize;__file__='c:\\users\\arthur~1\\appdata\\local\\temp\\pip-build-v1zg6s\\scipy\\setup.py';exec(compile(getattr(tokenize, 'open', open)(__file__).read().replace('\r\n', '\n'), __file__, 'exec'))" install --record c:\users\arthur~1\appdata\local\temp\pip-fcvwft-record\install-record.txt --single-version-externally-managed --compile" failed with error code 1 in c:\users\arthur~1\appdata\local\temp\pip-build-v1zg6s\scipy\
You are using pip version 8.1.1, however version 9.0.1 is available.
You should consider upgrading via the 'python -m pip install --upgrade pip' command.
Estou cometendo mais algum erro?
Obrigado,