**F-statistic and
Significance**

**F-statistic** is a value resulting from a standard statistical test used in ANOVA
and regression analysis to determine if the variances between the means of two populations
are significantly different. For practical purposes, it is important to know that this
value determines the P-value, but the F-statistic number will not actually be used in the
interpretation here.

** ^{†}Significance, **or P-value, is the probability that an effect at
least as extreme as the current observation has occurred by chance. Therefore, in these
particular examples the chance that the prevalence of low waz dropped from 38% to 26% in
for better roofing groups and from 40% to 16% in groups with higher education is unlikely
to have occurred by chance. For the roofing example,

^{†}Hennekens, C. H., *Epidemiology in Medicine*. Boston: Little,
Brown and Co., 1987.