Answer:
A = Not a paired sample
B = paired sample
C = Not a paired sample
Explanation:
Paired samples also commonly referred to as dependent samples are often characterized by having to different data points which are taken at different times, location and so on. Such that each pair of data points or observation can be matched based on the basis of the subject or sample name usually for the sake of analysing if any statistical difference exists between the occurrence of each observation.
For the instances given above ;
a.) this isn't a paired sample, because Professor Quick and Professor Quacks students are different, hence each student has only one reading and as such a match of the two test scores cannot be made on the basis of student name or identity. Hence, it is not a paired sample
B.) This is a paired sample, two different readings are available for each students ; one at the beginning, the other at the end. Hence, it is a paired sample
C.) This is not a paired sample, because the subjects used to obtain the weight of 10 year old in 1994 aren't the same samples used in 2009