A new treatment for baldness is known to be effective in 70% of the cases treated. Four bald members of the same family are treated. Let X = the number of successfully treated members. Is X a binomial random variable? Explain!

I'm sure you must have learned how to decide whether a variable should be considered a binomial variable or not.

Those include:
There must be only two outcomes, "success" or "fail"
Each event should be independent of each other.
The number of events is constant.
The probability for success should be the same for every event.

Based on those, what would be your answer? :)