A random sample of 30 executives from companies with assets over $1 million was selected and asked for their annual income and level of education. The ANOVA comparing the average income among three groups of executives with different levels of education showed a significant difference (F = 4.56, p < 0.05). What can be concluded from this analysis?
1) There is a significant difference in the average income among executives with different levels of education.
2) There is no significant difference in the average income among executives with different levels of education.
3) The ANOVA test is not valid for this analysis.
4) The sample size is too small to draw any conclusions.