Answer:
Comparing means from dependent samples.
Explanation:
In the scenario described above, the 25 sampled individuals were used to test the effect of weightlifting on alleviating back pain. The samples used were not changed nor altered during the study as the same subjects who were tested to measure their level of pain before lifting weight were the same group subjected to the actual weight lifting test and again had their level of pain tested. Since only one group was involved in the study ( a single group was tested on neutral and actual treatment). Hence, the study used dependent samples to compare the average level of pain.