a researcher wants to examine the effects of time pressure on test performance. three groups of college students complete a simple math test - addition and subtraction. as each participant arrives, the researcher randomly assignes them to group 1, 2, or 3. participants in group 1 are told they should work as fast as they can before the buzzer rings, but they are not told how long they have (and in fact, the buzzer does not ring at all so they are actually given as much time as they need). participants in group 2 are told to work as fast as they can, but they can take as much time as they need. participants in group 3 are told to complete the test and take as much time as they need. after receiving instructions, each participant is given a tablet where they take the test. their completing time and accuracy is measured - and the buzzer never rings. t what is the research design for this study?