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.
1 For example, the Ultra-Tow car tow dolly retails for $1,000 to $1,500. 2  To get an exact quote on rental or purchase, major companies such as Budget.com have calculators that you can use to see what it is going to cost you. 3  For the heavier vehicles that have to be towed away, it could be around $2,400 to $3100.