Matched pairs tests have which advantage over beforeafter te

Matched pairs tests have which advantage over before/after tests

Matched pairs tests require less time to execute than before/after tests.
       Matched pairs tests tend to have less error variance than before/after tests.
       Matched pairs tests require fewer subjects than before/after tests.
       Matched pairs tests have more degrees of freedom than before/after tests

Solution

Matched pair test compare the differences between the before and after values of the product. So, it has less error variance as opposed to other types of tests.

So,

Option A is correct.

Hope this helps.