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Frequently Asked Questions

Acceptance Sampling
PAS-2nd-Edition-Look-Inside

Check out the second edition of Practical Acceptance Sampling: A Hands-On Guide. Written by Prof. Galit Shmueli (creator of SQC Online), the book is a concise introduction to the inspection of products and services for quality assurance using statistically-based sampling plans.

Methods are illustrated using SQC Online, Microsoft Excel, and online calculators.

There's an e-book version available, as well as a printed book. Both are available at Amazon.com.

Try it free: Download the first chapter.

Yes. Applying a constant plan that does not take into account the history of batches is useless. The MIL-STD-105E switching rules and MIL-STD-1235C switching rules are an integral part of the sampling scheme.

Yes. Although the military standard itself was phased out in 1989, it's civilian counterparts, ANSI Z1.4 or ISO 2859 (which are essentially the same) still exist. In practice these sampling plans are widely used by many industries.

Yes. Some of our users apply acceptance sampling to processes such as auditing applications, checking errors on invoices, etc.

The problem lies in correctly using the tables. We suggest reading the standards carefully, and especially the legend and footnotes at the bottom of the particular table.
One common mistake, when arrows are present in the tables, is not adjusting the sample size according to the arrow. This is just one example.
Using our calculators is a safer alternative to the error-prone usage of the printed standards.

Accounts & Billing

To renew your expired subscription, follow these steps:

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  2. Once you are logged in, visit the the subscription page (www.sqconline.com/subscribe), choose your plan and click the Buy Now button.
  3. You will be take to the PayPal payment page. Follow the directions to complete the payment.
  4. Note: We use PayPal for processing credit card payments. If you do not wish to open a PayPal account, choose the "Don't have a PayPal account?" option on the payment page.

At this time we are not able to upgrade or otherwise change account types. Please choose your plan carefully.

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Note: We also offer a free access program.

To make it easy to manage your subscription, all users in a multi-user subscription share the same username and password. The account manager (the person who subscribed) is responsible for managing the account.
Our system automatically enforces the user limit for the account.

Website

Apologies, but the answer is no. We provide an "Statistical Quality Control in the Cloud" service. You can access our calculators from any Internet-connected device worldwide.

A few account types are shared by multiple users. In order to protect these accounts, users are not able to update the account's email. If you require any assistance, just send us a message.

Yes. Just go to your user page, enter a new username, and click "Save".

This issue affects only users of Internet Explorer. For best results, we recommend viewing our web site with either Google Chrome (download here) or Mozilla Firefox (download here).

Random quote

Quality has to be caused, not controlled.

— Philip Crosby