The average of allsubgroups becomes the centerline for the lower plotting area. Average of Ranges Example Step 7 - Calculate the upper control limit (UCL) and lower control limit (LCL)for the averages of the subgroups. At this point, your chart will look like aRun Chart. Now, however, the uniqueness of the Control Chart becomes evidentas you calculate the control limits.
Ford Motor Company recommends that the Crown Vic limit its towing to a trailer with a gross vehicle weight of 1500 lbs or less with a tongue weight not to exceed 150 lbs. See HERE.
Maintenance and repair costs vary depending on usage. For a luxury fifth wheel towed by a medium-duty truck approximately 25,000 miles a year, RVersOnline.org estimates basic repairs for both the truck and fifth wheel of $1,250 a year, with new tires every two years adding another $2,400.