Variations in differences between target web site data values and {HEAD ~ corresponding average and bounding web site data values} over {TAIL ~ time} determines improvement and success of the target web site 
Variations in differences between target web site data values and { HEAD ~ corresponding average and bounding web site data values } over { TAIL ~ time } determines improvement and success of the target web site
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH