Question

What is the value of the degree of freedom used in evaluation by Type-A method? (Where N is the number of independent measurements of quantity)

(a) N

(b) N+1

(c) N-1

(d) N+2

The question was posed to me at a job interview.

This intriguing question originated from Type A Evaluation of Uncertainty in chapter Evaluating Uncertainty in Measurement of Engineering Metrology

Answer 1

Right choice is (c) N-1

To elaborate: The number of degrees of freedom used for evaluation is one less than the number of independent measurements of quantity i.e. if number of independent measurements are 100 then the degree of freedom is equal to (100-1).