Answer: We can say that brain volume of 1367.6 cubic cm would be significantly high.
Step-by-step explanation:
Since we have given that
n = 20 brains
Mean = 1103.8 cubic. cm
Standard deviation = 121.9 cubic. cm
According to range rule of thumb, the usual values must lie within 2 standard values from the mean.
So, it becomes,
[tex]\bar{x}-2\sigma\\\\=1103.8-2\times 121.9\\\\=1103.8-243.8\\\\=860[/tex]
and
[tex]\bar{x}+2\sigma\\\\=1103.8+2\times 121.9\\\\=1103.8+243.8\\\\=1225.7[/tex]
We can see that 1376.6 does not lie within (860,1225.7).
So, we can say that brain volume of 1367.6 cubic cm would be significantly high.