11. Correct. The answer is false
Although sample variance is the most common used measure of dispersion, and large values of sample variance or sample standard deviation indicate more dispersion of the values of the sample about the arithmetic mean of the sample (GHJ page 23). However, this is not useful to do comparison between different populations, because their units of measures affect the variability.
Instead we have to use the coefficient of variation = CVx = (sample variance / sample mean) * 100.
CVa = (3,500 / 12,100) *100 = 28.92%
CVb = (3.2/ 7.5625) *100 = 42.31%
which indicates that the sample b (years of post-secondary education) is more dispersed about the mean than sample a (monthly earnings).