Perhaps you should try some spelling variations:
"processing base statistical methods." » "processing bayesian statistical methods.", "processing _ statistical methods.", "processing spain statistical methods.", "processing zones statistical methods."
"processing data statistical methods." » "processing capital statistical methods.", "processing health statistical methods.", "processing _ statistical methods.", "processing digital statistical methods.", "processing spain statistical methods.", "processing units statistical methods."

You may be able to get more results by adjusting your search query.

• If you are trying to use Boolean operators, they must be ALL CAPS: (("processing base statistical methods.") OR ("processing data statistical methods."))~.
• Removing quotes may allow a broader search: (( processing base statistical methods. ) or ( processing data statistical methods. ))~.
• Adding a wildcard symbol may retrieve word variants: (("processing base statistical methods.") or ("processing data statistical methods."))*.