# Which data needs to be collected and what to do with it. I need step by step process with explanation for understanding.

I sell a given product through 1000 shops & average revenue for that product is 2400 dollars per week per shop, with a standard deviation of 3100 dollars. I want to analyze, the offer ' three for the price of two' would be effective on my revenue or not, if it's introduced in 50 shops.

I understand that I should take average of 50 shops. But after that, I am not sure. How to go about it? .

• A linear model would be appropriate, where you would compare your regular product with your three for one "product" to check if there is a significant difference. – user2974951 Oct 4 '18 at 10:57
• @user2974951 But shouldn't there be data for the three for one scheme, to do any kind of linear regression? – GeneX Oct 4 '18 at 13:06
• Well yes, that was assumed. OP should collect data on these 50 shops for the three for one product and then perform the analysis. I don't see how he could do this without data? – user2974951 Oct 4 '18 at 13:11

$$d_i = a_{i} - b_{i}$$ $$a_{i} \textrm{----> revenue of shop "i", after scheme}$$ $$b_{i} \textrm{----> revenue of shop "i", before scheme}$$
$$\textrm{Now you have 50 data points --> } d_{i}$$
You can get the mean, standard deviation of these 50 data points and do the standard two-tail hypothesis testing on the mean(t-test), with the null hypothesis as $$d_i = 0$$.