Need help to identify an appropriate way to analyze data !

Hi group members,

I am shamima, a recent graduate in Biostatistics from University of Waterloo, ON, Canada and I am new to this forum. Currently I am working on a project. I have a data set on different thickness of paper production. There are 4 variables: thickness, backlog (in number of days), ME (machine efficiency in %) and SR (shipment readiness in %).

Day Thickness Backlog ME SR
01-Jan-13 700 13.57 93.50 100.00
01-Jan-13 750 13.57 93.50 100.00
02-Jan-13 700 12.48 93.65 100.00
03-Jan-13 650 11.47 82.68 100.00
03-Jan-13 700 11.47 82.68 100.00
03-Jan-13 750 11.47 82.68 100.00

As you can see i have duplication of backlog, me and sr data for thickness.
My research questions are: how these 4 variables are associated with each other and how much they affect each other?

Correlation and scatter plots does not suggest any clear relation among them. Also regression model is found to be not a good fit for this data.

I need help on other way of analyzing this data (if any!). I will be glad if respective members of this forum can help me on this.