Answer
Since the probability is not unusual, it implies that the population of adults 25 years and older in the United States having advanced
degrees has increased.
Work Step by Step
p̂ = 60/500 = 0.12
$σ_{p̂} = \sqrt \frac{p(1-p)}{n}$
$ = \sqrt \frac{0.10 * 0.90}{500} = 0.013$
To calculate $P(p̂ \geq 0.12)$, we need to find the z-score:
$z = \frac{p̂ - μ_{p̂}}{σ_{p̂}}$
$= \frac{.12-.10}{0.013}$ = 1.49
$P(z \geq 1.49) = 0.0681$, hence:
$P(p̂ \geq 0.12) = 0.0681$ (not unusual)
