Figure - PMC

Skip to main content

An official website of the United States government

Here's how you know

Here's how you know

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you've safely connected to the .gov website. Share sensitive information only on official, secure websites.

View full-text article in PMC

. 2014 Sep 6;9:81. doi: 10.1186/s13018-014-0081-8

Search in PMC
Search in PubMed
View in NLM Catalog
Add to search

© Zhang et al.; licensee BioMed Central Ltd. 2014

This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly credited. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.

PMC Copyright notice

CUSUM learning curve. Point A (case 16) corresponds to the main inflection point at which the failure rate begins to keep consistent. At point B (case 29), the line crosses the lower decision limit and the failure rate is equal to the defined acceptable failure rate (20%). The failure rate did not reach the unacceptable threshold (h1) at any time.