Answer
The coefficient of static friction must be at least 0.20.
Work Step by Step
The force of static friction between your feet and the floor will provide the force to accelerate you at a rate of 0.20g. Therefore,
$F_f = ma$
$mg\mu_s = ma$
$\mu_s = \frac{0.20g}{g}$
$\mu_s = 0.20$
The coefficient of static friction must be at least 0.20.
