OK. the error messages you got indicated there is package installer version mismatch issue during installing.
Type in this command:
this will show all installed components and their version in a list.
Basically it is because the python package manager (PIP) trying to download and install latest component, like pandas (0.23.4) in this case. However it is conflicts with the version of components that your Mac already installed (NumPy in this case). So you either upgrade all installed components to latest, or install an earlier version of pandas to resolve the conflict.
The latter method needs less efforts, as upgrade all components probably leads to upgrade major python version, which is not MAC default installation, so install easier version of pandas is recommended.
You can use this command to install a specific version of pandas:
sudo -H pip install pandas==0.19.2