Answer to Question #251083 in Statistics and Probability for Leatha

Question

Brain volumes of 20 brains have mean of 1081.3 and standard deviation of 128.4. What are the significantly low and high values? Would a brain volume of 1358.1 be significantly high?

Answer 1

$\mu=1081.3$

$\sigma=128.4$

Using the range rule of thumb, significantly low/high values are given as,

Significantly low value=$\mu-2*\sigma$

Significantly low value =1081.3-(2*128.4)=824.5

Significantly high value=$\mu+2*\sigma$

Significantly high value=1081.3-(2*128.4)=1338.1

The limit of values is 824.5 to 1338.1.

A value below 824.5 is considered low and a value above 1338.1 is considered high.

Therefore, the value of 1358.1is more than the upper limit, thus it is significantly high