lets say I have a table for number of customers visiting a shop per day. now I want to calculate that how much change has happened in terms of number of visitors throughout the past 30 days and come up with a single value that tells me the change rate (in percentage). but I do not want to compare the changes of current month with the values of the previous month(s) instead I want to compare the current month with itself! I have some naive solutions but I am not a data scientist and am not sure if the solution would give me a meaningful value at all!
my first question: is this a meaningful question at all (to compare a data set with itself)?
my second question: if so, how would you approach the solution?
solution one: one solution that I thought about was to compare the value of the first day with the value of the last day, but then It seemed a bit stupid because values could fluctuate randomly in between and the result would not represent the fluctuations.
solution two: another solution that I could think of was to compare the value of each day (within the month) with the value of the day before it and then calculate the change ratio and finally accumulate all the ratios and come up with a single value!
side note: i would like to get both positive and negative percentage depending on the change ratio