for my term paper, I want to compare broadband internet price data in the US. There are three datasets, each represent retail prices from 2016, 2017 and 2018. All data is clustered into 6 download speed classes and four product classes (itnernet only, internet with fixed telephony, internet with television, internet with fixed telephony and television). This gives me 24 subsets of data per year.
My research question is "have broadband retail offer prices changed significantly from 2016 to 2018 across the different speed classes?" and I am not very familiar with these tests for significance and absolutely new to statistics. But at it's core I need to compare the mean prices of all products in the different speed clusters. Which tests and methods should I apply here?
I started reading about one and two-sided t-tests, Wilcox, Shapiro-Wilk, KS-tests and many more but find it a bit confusing and hard to understand what they are actually used for and which could be relevant for my research question.
A second question: If i changed my research question from "changed significantly" to "improved significantly" (i.e. less expensive in 2018 compared to 2016), how would that affect the choice of statistical tests?
I hope someone can bring some light into this or refer to some useful and easy-to-understand literature. The analysis is supposed to be done using R.
My data looks something like this:
OfferID Price Product SpeedCluster NY001 20 Single 1 NY002 34 with FT 2 NY003 25 Single 1 NY004 40 with TV 3 NY005 42 Single 5 NY006 60 All 4 NY007 50 All 4
OfferID Price Product SpeedCluster NY001 19 Single 1 NY002 37 Single 2 NY003 24 Single 1 NY004 45 with TV 3 NY005 40 with TV 2 NY006 56 All 4 NY007 50 All 3
In every year, different price offers were collected directly from the Website of Internet Service Provider during two weeks. Time of year did not change over the years.
From this data, I did subsets, so all offers with internet only in speed cluster 1 are together, all offers with internet only in speed cluster 2, all offers with internet only in speed cluster 3, ...., all offers with internet and telephony in speed cluster 1, all offers with internet and telephony in speed cluster 2, ... and so on.