<s>
In	O
statistics	O
,	O
and	O
especially	O
in	O
the	O
statistical	O
analysis	O
of	O
psychological	O
data	O
,	O
the	O
counternull	B-General_Concept
is	O
a	O
statistic	O
used	O
to	O
aid	O
the	O
understanding	O
and	O
presentation	O
of	O
research	O
results	O
.	O
</s>
<s>
It	O
revolves	O
around	O
the	O
effect	B-Application
size	I-Application
,	O
which	O
is	O
the	O
mean	O
magnitude	O
of	O
some	O
effect	O
divided	O
by	O
the	O
standard	B-General_Concept
deviation	I-General_Concept
.	O
</s>
<s>
The	O
counternull	B-General_Concept
value	I-General_Concept
is	O
the	O
effect	B-Application
size	I-Application
that	O
is	O
just	O
as	O
well	O
supported	O
by	O
the	O
data	O
as	O
the	O
null	B-General_Concept
hypothesis	I-General_Concept
.	O
</s>
<s>
In	O
particular	O
,	O
when	O
results	O
are	O
drawn	O
from	O
a	O
distribution	O
that	O
is	O
symmetrical	O
about	O
its	O
mean	O
,	O
the	O
counternull	B-General_Concept
value	I-General_Concept
is	O
exactly	O
twice	O
the	O
observed	O
effect	B-Application
size	I-Application
.	O
</s>
<s>
The	O
null	B-General_Concept
hypothesis	I-General_Concept
is	O
a	O
hypothesis	O
set	O
up	O
to	O
be	O
tested	O
against	O
an	O
alternative	O
.	O
</s>
<s>
Some	O
researchers	O
contend	O
that	O
reporting	O
the	O
counternull	B-General_Concept
,	O
in	O
addition	O
to	O
the	O
p-value	B-General_Concept
,	O
serves	O
to	O
counter	O
two	O
common	O
errors	O
of	O
judgment	O
:	O
</s>
<s>
assuming	O
that	O
rejection	O
of	O
the	O
null	B-General_Concept
hypothesis	I-General_Concept
at	O
a	O
particular	O
p-value	B-General_Concept
means	O
that	O
the	O
measured	O
"	O
effect	O
"	O
is	O
not	O
only	O
statistically	O
significant	O
,	O
but	O
also	O
scientifically	O
important	O
.	O
</s>
