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246 PART III: Experimental MethodsKEY CONCEPTSrepeated measures designs 226sensitivity 227practice effects 230counterbalancing 230differential transfer 243REVIEW QUESTIONS1 Describe what is balanced in a random groups design and what is balanced in arepeated measures design.2 Briefly describe four reasons why researchers would choose to use a repeatedmeasures design.3 Define sensitivity and explain why repeated measures designs are often more sensitivethan random groups designs.4 Distinguish between a complete design and an incomplete design for repeatedmeasures designs.5 What options do researchers have in balancing practice effects in a repeated measuresexperiment using a complete design?6 Under what two circumstances would you recommend against the use of ABBAcounterbalancing to balance practice effects in a repeated measures experiment usinga complete design?7 State the general rule for balancing practice effects in repeated measures experimentsusing an incomplete design.8 Briefly describe the techniques that researchers can use to balance practice effects inthe repeated measures experiments using an incomplete design. Identify which ofthese techniques is preferred and explain why.9 Explain why an additional initial step is required to summarize the data for anexperiment involving a complete repeated measures design.10 Describe how researchers can determine if differential transfer has occurred in arepeated measures experiment.CHALLENGE QUESTIONS1 The following problems represent differentsituations in the repeated measures designs inwhich practice effects need to be balanced.A Consider a repeated measures experimentusing a complete design involving oneindependent variable. The independentvariable in the experiment is task difficultywith three levels (Low, Medium, and High).You are to prepare an order for administeringthe conditions of this experiment so that theindependent variable is balanced for practiceeffects. You are first to use block randomizationto balance practice effects and then to useABBA counterbalancing to balance practiceeffects. Each condition should appear twice inthe order you prepare. (You can use the first rowof the random number table (Table A.1) in theAppendix to determine your two random ordersfor block randomization.)B Consider a repeated measures experimentusing an incomplete design. The independentvariable in the experiment is the font size inwhich a paragraph has been printed, and thereare six levels (7, 8, 9, 10, 11, and 12). Presenta table showing how you would determine theorder of administering the conditions to thefirst six participants of the experiment. Be surethat practice effects are balanced for theseparticipants.2 The pursuit rotor is a test of perceptual-motorcoordination. It involves a turntable with a diskabout the size of a dime embedded in it. Theparticipant is given a pointer and is asked tokeep the pointer on the disk while the turntable is