Spring 2001
Lecture Notes - EMSE 282 - Professor Thomas A. Mazzuchi - 1
VARIABLE AND OTHER SAMPLING PLANS
VARIABLE SAMPLING PLANS
Merits
• Advantages
- Same OC Curve can be obtained with smaller sample size.
- Variable data provide more information.
• Disadvantage
- cost/observation greater.
- distribution of quality quantity must be known or assumed.
- separate plan used for each quality measure.
- may lead to a rejection of lots with no defectives.
Types
• Control of lot or process
fraction defective.
• Control of lot or process
parameter.
Assumptions
• Quality characteristic is (usually) normally distributed

This
** preview**
has intentionally

**sections.**

*blurred***to view the full version.**

*Sign up*
Spring 2001
Lecture Notes - EMSE 282 - Professor Thomas A. Mazzuchi - 2
Control of Process Parameters (Usually , )
. 5
• Based on hypothesis testing
• Design for process mean, one sided,
known
5
- Given X
N(
,
) specify a lower limit X
for X (reject if
X
X )
µ
Î8
. 5
#
L
L
- Given we want to accept batches of quality
with probability 1
and
.
α
1
batches of quality
with probability
, find n, and X
.
"
2
L
Pr{X
X |
}
Pr{
}
œ
œ
L
1
X
X
/
n
/
n
.
.
.
.
5
5
1
1
L
È
È