Answer
$P(p̂ \geq 0.31) = 0.0681$. Hence it iwll not be unusual, as the probability > 0.05.
Work Step by Step
To calculate $P(p̂ \geq 0.31)$, we need to find the z-score:
$z = \frac{p̂ - μ_{p̂}}{σ_{p̂}}$
$= \frac{.31-.28}{0.02}$ = 1.49
$P(z \geq 1.49) = 0.0681$, hence:
$P(p̂ \geq 0.31) = 0.0681$ (not unusual)
