I'm really really really sad :"(

The variable in a relation who’s value depends on the value of the independent variable is called what?

The random variable x is the number of occurrences of an event over an interval of ten minutes. it can be assumed that the probability of an occurrence is the same in any two-time periods of an equal length. it is known that the mean number of occurrences in ten minutes is 5.3. the appropriate probability distribution for the random variable

This is so hard and it’s for a test