Answer:
It is negative when s12 is smaller than s22.
Step-by-step explanation:
The F distribution has the following properties.
1) It is always right-skewed. but as the degrees of freedom v1 and v2 become large F distribution approaches normal distribution.
2) It describes the ratio of two variances.
3) It is a family based on two sets of degrees of freedom.
4) It is negative when s12 is smaller than s22. This is not true sometimes as the F distribution does not depend on the population variance but on the two parameters v1 and v2.