Create a representative little base from an other base

Hello,

I'm a Phd student working now with a large dataset, with a list of loans given to corporations over 15 years (specific type of loans and clients in a specific region). I have 130.000 lines in the excel files, loans go from 1250$ to 20 millions.

I wanna reduce this sample to, for instance, n=300, in order to add some variables by hand. How can I do that ? I would like the statistical distribution of loans values to be the same in the main database and in the little one.

Thanks,
Best,


rr