Online tables and calculators for SPC/SQC
SQC Online offers easytouse calculators for various popular quality control procedures, based on ISO and other widely used standards.
Acceptance Sampling: Accept or Reject Batches
Acceptance sampling is used by industries worldwide for assuring the quality of incoming and outgoing goods. Acceptance sampling plans determine the sample size and criteria for accepting or rejecting a batch based on the quality of a sample, using statistical principles.
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Many organizations require the use of ISO standards (or their ANSI/ASQC/BS/Military Standards or other counterparts) for purposes of certification. Below are online versions of Military Standard Tables (equivalent to the civilian ISO/ANSI/ASQC/BS standards), which greatly simplify the process of determining sampling plans. You can find out how many items to sample and inspect, and how to decide whether the entire batch should be accepted or rejected.
Calculator  What is it for? 


Sampling plans for attribute (pass/fail) data 
MILSTD414 ANSI/ASQC Z1.9, ISO 3951, BS 6002 
Sampling plans for measurement data 
Procedure CSP1 
Sampling plans for continuous production 
DodgeRomig Single Sampling AOQL  AOQLbased rectifying plan for attribute (pass/fail) data 
DodgeRomig Single Sampling LTPD  LTPDbased rectifying plan for attribute (pass/fail) data 
MILSTD1916 for Attributes  AcceptonZero (c=0) sampling plans for attribute (pass/fail) data 
MILSTD1916 for Variables  AcceptonZero (c=0) sampling plans for measurement data 
AcceptonZero (c=0) sampling plans for continuous production  
AQLbased AcceptonZero (c=0) sampling plans for attribute (pass/fail) data 
Procedure  What is it for?  Example 

MILSTD105E Switching Rules (ANSI/ASQC Z1.4) ISO 28591 Switching Rules (BS 60011) 
Switching rules between levels of inspection  "Switch from normal to tightened inspection following 5 consecutive accepted batches" 
MILSTD1235C Switching Rules Procedure CSP1 
Switching rules between phases of sampling  "Switch from 100% inspection to partial sampling after 5 consecutive conforming items" 
Switching rules for batch (attributes and variables) sampling plans  Switch from normal to reduced inspection following 10 consecutive nonrejected batches 
Control Charts: Is Your Process Out of Control?
A control chart is a popular statistical tool for monitoring the quality of goods and services, and for detecting when the process goes "out of control" as early as possible. Samples from the process are taken every time interval, and their quality measured. Control charts are used to track the sample quality over time and detect any unusual behavior. Below are calculators that help you to easily obtain the control chart limits for different types of measurements.
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Calculator  What is it for?  Example 

Control Charts for Variables  Compute limits for x, S and R control charts  
Control Charts for Attributes  Compute limits for c, p, u and np  
Western Electric Company (WECO) Rules  The detections of small shifts  "Signal an alarm if 8 consecutive points fall on one side of the center line" 
Process Capability
Does Your Process Meet Specifications?
Calculator  What is it for? 

Process Capability Index  Find out if your process meets the specifications by calculatingCp and Cpk 
Reliability of Systems and Components
Calculator  What is it for?  Example 

ConsecutiveType System Reliability  Compute the failure rate of consecutivetype systems  "The system fails if 3 consecutive components fail" 
Calculate MTBF and failure rates for electrical and electronic components, devices, and equipment  
MTBF Calculator  Calculate MTBF for a system, given the part (component) failure rate 
Learn about RunRelated Distributions
Many procedures in industry are based on the concept of a "run". A run is a sequence of identical events, such as a sequence of winnings in a slot machine. Many such procedures are based on rules of thumb, rather than on theory. Below is a calculator based on innovative theory developed in this field. The application shows what you should expect if applying a runbased procedure.Procedure  What is it for 

Waiting for the First Run  How long until you see the next run? Find the waiting time distribution for a specified run, given a sequence of independent success/failure events with the same probability of success ("IID bernouli trials") 