Which of the following is a method of collection of primary data?
There are 35 students in a hostel. If the number of students increases by 7, the expenses of the hostel increases by Rs. 42 per day while the average expenditure per head diminishes by Re. 1. The original expenditure of the hostel is:
If 4,5,6,6,6,6,6,6,6,7 be a random sample from a poisson population with parameter λ, then an unbased estimate of λ is :
