EViews.com

I am relatively new to Eviews software and econometrics in general, so apologies in advance for any lack of basic knowledge.

I have created a model based on Economic growth in countries over a 5 year period regressed on various variables such as education, manufacturing etc.
The model looks good as all the variables are significant at a 95% confidence interval, easily passes the Wald test and high r squared value.

Obviously for cross sectional data there are more tests available such as the ramsey reset test and heteroskedasticity tests, but I have found the amount of tests available for panel data is limited.
I have tried the Redundant fixed effect test and the Hausaman tests but I am having trouble understanding the difference between fixed and random models, could some please explain the difference?

The results I got were:
Fixed: Cross section F=0.6874 and cross section chi-squared=0.4124
Random (Hausman): 0.056 however I received a message ** WARNING: estimated cross-section random effects variance is zero.

Could someone please explain the warning message and what the results mean?

Thank you in advance!!

The random effects estimator is appropriate when the unobserved effect is thought to be uncorrelated with all the explanatory variables.
Hausman test checks whether the unobserved effects is correlated with the explanatory variables. If it is correlated then the fixed effects estimator is appropriate because of the omitted variable bias problem.