How to obtain a resulted report from 2 analyses without using the Combined Analyses feature ?

An alternate way is to adopt the following procedure with a main report and a sub-report. Example based on Lead record type, but it also applies to others, such as accounts, opportunities, contacts.

1.Create a report that gives all Leads that do have activities associated to them.  This will be the sub-report. Save this report in your folder.

2. Create a second report (this will be the main report) with all the desired fields.

3. Click on "New Filter" under the Lead ID column.

4. Go down to the bottom of the "Create/Edit Filter" window and click on "Advanced".

5. Choose "Filter based on results of another request".