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.
As an AAA Plus member, you can tow up to 100 miles and receive lock-out assistance. Premier members get up to 200 miles of free towing and 24-hour concierge service. The cost of each plan varies depending on where you live, but they range from under $50 to more than $130.