D DJN Jan 29, 2003 #1 Jan 29, 2003 #1 What is considered to be the minimum number of subgroups to assess process capability? I have been using 20 but have now been informed that 25 should be used. Is this correct?
What is considered to be the minimum number of subgroups to assess process capability? I have been using 20 but have now been informed that 25 should be used. Is this correct?
M M Greenaway Jan 29, 2003 #2 Jan 29, 2003 #2 The QS9000 SPC manual generally recommends at least 25 sub-groups.
D D.Scott Jan 29, 2003 #4 Jan 29, 2003 #4 Hi David - welcome to the Cove. An automotive PPAP using an X-bar and R chart would require a minimum of 25 subgroups containing at least 100 consecutive samples. Dave
Hi David - welcome to the Cove. An automotive PPAP using an X-bar and R chart would require a minimum of 25 subgroups containing at least 100 consecutive samples. Dave