I have data collected for 20 subjects under two conditions for each of the subject. When I want to compare the means of the two conditions, is it absolutely necessary that I use the paired T-test? My understanding is that in paired T-test it is easier to establish significance than the independent T-test because the former is affected by between subject variabilities as well. Under this argument, I believe that using independent T-test and establishing significance is stronger and valid. Am I correct?
Along the same line of argument, can I use one-way ANOVA instead of repeated measures ANOVA even when data has been collected for all subjects under all the conditions? I am tempted to check one way ANOVA instead of repeated measures ANOVA because one way ANOVA lets me compare multiple dependent variables at once where repeated measures ANOVA requires me to make subject X condition tables for each of those variables (in SPSS).