# Calculating probability from a distribution

I have a histogram/count plots of average time a property is in the market. Given this distribution, I'd like to calculate the probability that a similar property will be leased within 'x # of weeks' or less.

Would a cumulative probability distribution make sense, in this case or there are other ways of calculating?

i.e P(X <= x), where X is a similar property and x = # of weeks).

Say, I want to calculate the P(X <= 4), i.e probability that the property is on the market for less than 4 weeks.

Additionally, I'd also like to calculate conditional / bayesian prb. i.e given a set of property features, calculate the P(X <= 4) based on prior distribution. How would we formulate this as a conditional probability distribution problem?