Answer:
The number of data pairs minus 1.
Step-by-step explanation:
Paired test is a hypothesis test for comparing two pairs of data. NOrmally same items selected are subject to two different treatments and means are recorded and the differences are found out.
The differences are normally distributed and hence hypothesis test is done normally with d = difference =0 as null and alternate not equal to 0, or >0 or less than 0 as the need may be
The test statistic is the same as d difference between observed and 0 divided by standard error of the sample
Here degree of freedom would be n-1 where n is the number of data in any one pair
Hence correct answer is
The number of data pairs minus 1.
