Control Charts

Question 1

Control Charts designed for tracking single points of continuous data. They consist of two separate charts; A chart which tracks the individual data points (or pre-summarized data) and a chart which tracks the absolute value of the distance between each pair of consecutive data points. These are considered the most flexible of the Control Charts and are often used to track business performance data.

A classic example is to track daily total sales.

Answer 1

I & MR Chart (aka X & MR or Chart)

Question 2

Control Charts designed for tracking the average of sub-grouped continuous data. They consist of two separate charts; “X-Bar” stands for the “Average” Chart which tracks the mean of sub-groups of up to 6 data points and “R” stands for “Range” Chart which tracks the difference between the maximum and minimum values in the subgroup. These charts are not as sensitive to non-normal data as the I & MR Charts.

A classic example is to track the average cycle time to deliver packages by sampling 5 packages per day.

Answer 2

X-Bar & R Charts

Question 3

Control Charts designed for tracking the average of large sub-groups of continuous data. They consist of two separate charts; “X-Bar” stands for the “Average” Chart which tracks the mean of sub-groups of 6 or more data points and “S” stands for the “Standard Deviation” Chart which calculates the standard deviation within each subgroup. These charts are useful for detecting shifts in the “center” or average with large subgroups.

A classic example is to track the food order cycle time to deliver packages by sampling 10 orders per day.

Answer 3

X-Bar & S Charts

Question 4

Control Charts designed for tracking the proportion defective for discrete data.These charts require both the total population as well as the count of defective units in order to plot the proportion.

A classic example is to track the proportion of defective products returned each month.

Answer 4

P Chart

Question 5

Control Charts designed for tracking the number of defective items for discrete data in consistently sized sub-groups.

A classic example for use of this chart is to track the number of defective products per lot shipped where the lot size was constant.

Answer 5

nP Chart

Question 6

Control Charts designed for tracking the count of defects for discrete data in consistently sized sub-groups.

A classic example for use of this chart is to track the number of defects per application, which are all 10 pages each.

Answer 6

C Chart

Question 7

Control Charts designed for tracking the number of defects per unit for discrete data.

A classic example is to track the number of scratches on new smart phone cases at a manufacturing facility.

Answer 7

U Chart