Seems like you are offering the same data manipulation people currently do either with desktop software or custom coded server apps. Your value here is turning

Seems like you are offering the same data manipulation people currently do either with desktop software or custom coded server apps. Your value here is turning it into a web service and making it easier to use. There is a very strong case for doing just that. What I would recommend is to connect the dots and clearly position your service as cloud alternative to desktop / server data manipulation packages. Get very explicit about it and target similar customers. Do not limit yourself to just data on the web and allow file uploads. Make a feature-light free version and charge for a premium one, determined by data volume or number of manipulations or something like that. I think there is a lot of room for cloud-based statistical service to undercut traditional players in this market.