Form with range change based on dates

Hey there, just thought I would see if any of you guys can help me with my problem on excel. If there is anyone who can, it will be on here. I'll try my best to explain what I need the best I can. I have attached the file for reference and clarity sake. I want to be able to make a "form" in a sense, and all you have to do is enter in a quarterly date range, (look at my excel document, the first tab there is a "start date" and an "end date"), and based on that date range, calculate "Beta" (click on the Statistical Analysis tab) and each of the other calculations based on only the date range specified. I know I can go in a manually find and replace the cells, but my boss wants to be able to pick a range of quarterly dates and have all the data in one spot. Hope I explained it well enough. Let me know if there needs to be any more clarifying. Thanks in advance!!