[Analysis/Statistics] How to analyze a set of data where you have differing variable?

[appleguru]

Hi all,

Note: This is not for a class/work. I just stumbled upon this question and I've been itching to try and figure it out. My statistics are very rusty. I do not know if this is the right place to post so sorry in advance if it's not.

Objective: A bar franchise decided to install tablets in a bunch of their franchises. I'm trying to analyze the difference between bars in sales when a tablet was installed at each bar and determine the impact between franchisee from those who installed a tablet and those who didn't.

Here's what I'm given:

A spreadsheet with two tabs.

Tab1 is labeled Bar Sales.
In this tab you have all of the sales gathered throughout the 3years with a number of bars that were recorded (20~ bars). Each record has the column name (Bar Name, Date, Net Sales, #Transaction, Labor Cost)

Tab2: Bar info.
In this tab you have the information of Bars 1-20. Each record is of each bar with BarName, DateImplmeneted, Owner,Location, #ofTablets installed.

I guess what I'm trying to ask here is two questions. Example #1: I have all the sales data from Bar #15 from Jan1, 2013 to Dec 31st, 2014. Second tab shows that Bar #15 installed tablet on January 1st, 2014. How do I analyze the difference in sales before and after the tablet was installed? Also, how would I compare this to say Bar #1 who never installed the tablet?

Thanks in advance!

[Richard Buttrey]

Assuming other things are equal apart from the use of the tablet in the second year isn't this just a question of summing each of he two years and comparing them