I have encountered problem installing numpy package to pycharm and finally figured out. I hope it would be helpful for someone having the same problem in installing numpy and other packages on pycharm.
Pycharm Setting :
Go to File => Setting => Project => Project Interpreter. On this window select the appropriate project interpreter. After this, a list of packages under the selected project interpreter will be shown. From the list select pip and check if the version column and the latest version column are the same. If different upgrade the version to the latest version by selecting the pip and using the upward triangle sign on the right side of the lists. Once the upgrading completed successfully, you can now add new packages from the plus sign.
I hope this would be clear and useful for someone.