Dear Customer,
 
An explanation of functions used in the model
The aim is to explain that price can act as an independent variable
http://www.economicsdiscussion.net/goods/demand-function-and-demand-curve-economics/22093
http://www.economicsdiscussion.net/law-of-demand/demand-meaning-laws-and-demand-function/19383
Definition of an independent variable https://web.csulb.edu/~msaintg/ppa696/696regs.htm
Screen shot of function
 
As you can see, price can act as an independent variable.
 
For Ramadan, Hajj, and Ashoura, I actually searched every single day since 1998 to 2018 when there was these holidays. I then put a Dummy for them: 1=day with a holiday, 0= day with no holiday.
If you check the data in excel, you will observe that there are days when TASI did not operate. If I used weekly data, our error would be so big. We would have a problem especially with Ashoura and Hajj ceremonies. Working with daily data is more tedious but more precise.