Having nothing else given, an appropriate hypothesis is to assume that we have random variable 


    X = "the number of failures per week" 


with integer random values which is uniformly distributed with the minimum value of 0 and the maximum value of 4.



Then the mean average  is exactly 2  (=  ), as the problem states, 

and  the condition becomes "consistent with the given part" and "self-closed".



Then the answer to the problem's question is   P(X <= 1) =   (X may have values of 0 or 1  of 5 possible integer values from 0 to 4).