Answer
a) .5239
b) .8944
c) Yes
Work Step by Step
a) We first find the value of z:
$z =\frac{.8565-.8535}{.0518/\sqrt{1}}=.06$
Using the table of z-values, we see that the probability is .5239.
b) $z =\frac{.8565-.8535}{.0518/\sqrt{465}}=1.25$
Using the table of z-values, we see that the probability is .8944.
c) Yes, since the rate is almost 90 percent, it seems that the claim is fair.
