When interviewing, I find it most fitting to have a purpose or goal for the interview (for you, not them). I think that establishing this will help guide your questions and responses back to this individual. (E.x: I want to know if this person has ever used technology X to find inconsistencies in data, and how they did it.)
So the internship is around ..
investigating application of existing data analysis methods to cases occurred on our machines, for the sake of automating the analysis
Which says to me that these individuals need
- Critical Thinking/Problem Solving skills
- Troubleshooting and Reporting Skills
- Ability to read/comprehend/absorb ambiguous amounts of data (I could be wrong here)
- Ability to do a wide analysis between different...systems?
- Possibly experience working with a specific technology?
I think it's important to note that there are also different types of interviews:
- Strictly Verbal and in Person
- Some sort of written/visual/white-boarding test/session
- A combination of the 2
- Over the phone
When people are coming out of school, it's not always the case that they have ever worked in a professional environment, which does affect the interview in the sense that they might not have solved any "real-world problems." If this person is expected to be somewhat familiar with algorithms/technologies - I'd start there (after getting some background, etc). If this person is supposed to look at two separate data sets and report back inconsistencies - perhaps scale a "real-life" (but solvable) scenario down to interview-scale and let the individual try to "solve" it like they would on the job (setting realistic expectations is key here - and a whiteboard would be optimal).
Consider the person's [possible] experience - this is very important. Expectations should be set based on this and the questions you ask should be a merge between the expectations of the role and what someone coming into the role with very limited experience should be able to do. This is helping set both the company and this person up for success. If the role requires someone working with Excel in an advanced setting, talk through how to create a macro for a realistic problem-solving purpose. If the role requires knowing how to sort data in some form or fashion, ask questions about different optimization algorithms (just ask if they are familiar with any and proceed from there).
Finally, the thing to consider here is that everyone was once in their position. If they are sitting in front of you, it's more than probable they already want the job - it's up to you to determine if they have the critical thinking skills/personality/tactfulness/professionalism that you are going to expect and want to work with. At the end, ask yourself, if I were to hire this person right now, are they going to be successful or do they have the tools to grow into a successful person with some appropriate guidance?