There are twenty-one questions in three parts. The following points need to be n

There are twenty-one questions in three parts.
The following points need to be noted：
1.Use the following library to solve the problem：Numpy,Scipy,Pandas.
2.do not remove or delete or add any cell in this notebook: you should work on a separate, private notebook and only when you are finished debugging then copy the function implementations in the cells of this notebook. Make sure to copy only the function implementation and nothing else.
remove the raise NotImplementedError() under the # YOUR CODE HERE and replace it with your code: note that if you leave this command in the cell you will fail the associated test
3.Scoring criteria
Each function is awarded a number of marks.
A hidden unit test is going to evaluate if all desired properties of the required function are met.
If the function passes the test the associated marks are awarded, if it fails 0 marks are awarded.
The coding style (including clarity, conciseness, appropiate use of commands and data structures) will also be kept into consideration to award full marks.
If you make a typo error (e.g. mispelling a variable) this will likely causes a syntax error, the function execution will fail and you will be awarded 0 marks.
Do not make assumptions on the state of previous cells, i.e. expect each function to be evaluated independently, moreover expect each function to be tested in the unit tests on some randomly generated input.
Notebooks not conforming to the required format (see notes on how to use the notebook) will be penalised.