# frecuency and numbers - Numpy - mean, histogram and more

Hi experts!

If i have two numpy arrays: A = califications, B = number of alumns with calification 'a' (I mean: B[j] is the number of alumni in the class with test calification a[j]):

How can i calculate the MEAN VALUE and STANDARD DEVIATION of califications, and build a histogram of califications using numpy.

Waiting for your answers.

Thanks a lot!