<s>
In	O
statistical	O
quality	O
control	O
,	O
the	O
np-chart	B-Application
is	O
a	O
type	O
of	O
control	B-General_Concept
chart	I-General_Concept
used	O
to	O
monitor	O
the	O
number	O
of	O
nonconforming	O
units	O
in	O
a	O
sample	O
.	O
</s>
<s>
It	O
is	O
an	O
adaptation	O
of	O
the	O
p-chart	B-Application
and	O
used	O
in	O
situations	O
where	O
personnel	O
find	O
it	O
easier	O
to	O
interpret	O
process	O
performance	O
in	O
terms	O
of	O
concrete	O
numbers	O
of	O
units	O
rather	O
than	O
the	O
somewhat	O
more	O
abstract	O
proportion	O
.	O
</s>
<s>
The	O
np-chart	B-Application
differs	O
from	O
the	O
p-chart	B-Application
in	O
only	O
the	O
three	O
following	O
aspects	O
:	O
</s>
