Imagine that a researcher conducts an experiment using a within-groups design. specifically, the same participants provide related scores on a dependent variable at two different levels of an independent variable. ( assume that a relevant population standard deviation is not known). which of the following analyses would be appropriate for comparing means for both levels of the independent variable?
1) a z test
2) a one-sample t test (using raw means for the two levels of the independent variable)
3) a paired-samples t test
4) an independent-samples t test