Answer
0.0099, the evidence is strong.
Work Step by Step
p=0.2
$q=1-p=1-0.2=0.8$
$n⋅p=1000⋅0.2=200≥5.$
$n⋅q=1000⋅0.8=800≥5.$
Hence, the requirements are satisfied.
mean: $\mu=n\cdotp=1000\cdot0.2=200.$
standard deviation: $\sigma=\sqrt{n\cdot p\cdot q}=\sqrt{1000\cdot0.2\cdot0.8}=12.65.$
170.5 is the first value more than 17%, hence:
$z=\frac{value-mean}{standard \ deviation}=\frac{170.5-200}{12.65}=-2.33.$
By using the table, the probability belonging to z=-2.33: 0.0099, hence the probability: 0.0099. This probability is really close to 0, hence the evidence is strong.