Answer
0.0107, the evidence is strong.
Work Step by Step
p=0.2
$q=1-p=1-0.2=0.8$
$n⋅p=50⋅0.2=10≥5.$
$n⋅q=50⋅0.8=40≥5.$
Hence, the requirements are satisfied.
mean: $\mu=n\cdotp=50\cdot0.2=10.$
standard deviation: $\sigma=\sqrt{n\cdot p\cdot q}=\sqrt{50\cdot0.2\cdot0.8}=2.83.$
3.5 is the first value more than 3, hence:
$z=\frac{value-mean}{standard \ deviation}=\frac{3.5-10}{2.83}=-2.3.$
By using the table, the probability belonging to z=-2.3: 0.0107, hence the probability: 0.0107. This probability is really close to 0, hence the evidence is strong.
