Although numpy.ndarray has a mean, max, std etc. method, it does not have a median method. For a list of all methods available for an ndarray, see the numpy documentation for ndarray.

It is available as a function that takes the array as an argument:

>>> import numpy as np
>>> a = np.array([1,2,3,4,5,6,7,8,9,10])
>>> np.median(a)
5.5

As you will see in the documentation for ndarray.mean, ndarray.mean and np.mean are "equivalent functions," so this is just a matter of semantics.

Correct syntax:-

print(np.median(array))

It would be helpful if you could post the full stack trace, so that we can see which line your error occurs at. In general, the more information you can provide in a question, the better.

In this case, it looks like your full_model_pipeline may somehow become a numpy array. Since you have a one-element pipeline, you could try changing

full_model_pipeline = Pipeline(steps =[
                        ('full_pipeline',full_pipeline),
                        ('model',LinearRegression())
                    ])

full_model_pipeline.fit(X_train,y_train)

to

model = LinearRegression()
model.fit(X_train, y_train)