mean X⎯⎯⎯.
X
-
.
The value x⎯⎯=152
x
-
=
152
happens only one way (the rower weighing 152 pounds must be selected both times), as does the value x⎯⎯=164
x
-
=
164
, but the other values happen more than one way, hence are more likely to be observed than 152 and 164 are. Since the 16 samples are equally likely, we obtain the probability distribution of the sample mean just by