What started as a small university project is now one of the most-used sites in the world for statistical process design. Guess the site itself is less flashy - but absolutely solid content on statistical quality control.

1. TQM Assignment – Handout on sqconline.com
Avik Chakrabarti Basant Baweja Deepesh Gajwani Rashi Sethi Sarang Bhutada Swarnali Choudhury
MS08A009 MS08A010 MS08A016 MS08A040 MS08A044 MS08A055
SQCOnline.com is a free, easy-to-use website that provides sampling plans to a large spectrum of users. It was
originally created as a part of Prof. Galit Shmueli’s doctoral thesis and now has been widely accepted in the
industry for creating different acceptance sampling plans for quality control.
Types of Accepting Sampling Plans that can be compiled using SQCOnline:
Sampling by attributes vs. Sampling by variables Incoming vs. Outgoing Inspection
Rectifying vs. Non-rectifying sampling plans Single, Double and Multiple sampling plans
This website supports a batch size of 2 to 5lac +
AQL varies from .01% to 1000%
Inspection Levels are from I to III and S-1 to S-4
Types can be Normal, Tightened or Reduced
This application gives the Single and Double Sampling Plans for attributes, as per the Military Std 105E as follows:
Operating Characteristic curves using SQCOnline: SQCOnline provides various sampling plans for different
requirements. All of them can be tabulated and compiled together to form the operating characteristic curves.
These curves for normal inspection indicate the percentage of lots or batches which may be expected to be
accepted under the various sampling plans for a given process quality.
For instance: The operating characteristics curves for accepted quality level greater than 10.0 may be based on
the Poisson distribution and may be applicable for defects per hundred units inspection while those for accepted
quality level of 10.0 or less and sample sizes of 80 or less may be based on the binomial distribution and are
applicable for percent defective inspection.

2. SQCOnline can be effectively used to decide in choosing between types of inspection and switching between
them. There are standard rules for for switching between samples and SQCOnline can validate action permitting Used when
Used when the switching. recent quality
recent quality has been poor
has been
exceptionally
good
If we answer the stipulated questions for switching between inspections, the site gives a probability plot on the
time period (when an inspection method could be switched).
Process capability index: The calculators on SQCOnline compute the process capability index which shows the
process potential of meeting the specifications. An example is as follows:
USL = 1.4 LSL = 0.60 σ = 0.10 Mean = 1.00 Cpk = 1.333 Cp = 1.333
The potential process capability can be achieved by centering the process. The PPM calculations are for the
potential process capability. As per the calculations, the process fallout is approximately 63 PPM (defective parts-
per-million)
Control Chart Calculator for Attributes (Discrete Data): This wizard computes the Lower and Upper Control
Limits (LCL, UCL) and the Center Line (CL) for monitoring the fraction of nonconforming items or number of
nonconformities (defects) using p and c control charts .
Control Chart Calculator for Variables(Continual data): This wizard on SQCOnline computes the Lower and
Upper Control Limits (LCL, UCL) and the Center Line (CL) for monitoring the process mean and variability of
continuous measurement data using Shewhart X-bar, R-chart and S-chart. It takes in a set of preliminary samples
drawn while the process is known to be in control. The information from these samples is used to estimate the
process mean and standard deviation:
This gives the upper control limit
Input
parameters for
This gives the central control limit
determining
controls
This gives the lower control limit
MTBF Calculator: SQCOnline can be used to calculate the system
reliability i.e. the mean time between two system failures. An example
of the same is described alongside.