National Statistics Day $($Hint$.$ Total equal days in year$)$

a$.$ If a person is randomly selected, find the probability that his or her birthday is October $18,$ which is National Statistics Day in Japan. Ignore leap years.

b$.$ If a person is randomly selected, find the probability that his or her birthday is in October. Ignore leap years.

c$.$ Estimate a subjective probability for the event of randomly selecting an adult American and getting someone who knows that October $18$ is National Statistics Day in Japan.

d$.$ If ten adult Americans are randomly selected and nine of them know that October $18$ is National Statistics Day in Japar, is that result of nine significantly high?