(Prob set ch11 Q7) please indicate which answer choice (A-D) is the best selection.

Problem Set: Chapter 11 The t Test for Two Related Samples Back to Assignment Attempts Keep the Highest / 1 7. Assumptions underlying the repeated-measures t test Suppose a sleep researcher wonders whether playing classical music while getting ready for bed helps people fall asleep faster. She has 20 study participants sleep two nights in the sleep lab. For one of those nights, the researcher has each study participant listen to classical music for 15 minutes before getting into bed. For the other night (the control night), the room is quiet. (The researcher varies which night the study participants listen to the music so that 10 of the participants have the control night first and the other 10 have the classical music night first.) The researcher then measures the study participants' sleep latency-that is, the number of minutes it takes for them to fall asleep. At the end of the study, the researcher looks at the distribution of the sleep latencies and notices that some people fell asleep immediately, whereas others took over an hour to fall asleep. In addition, the differences in each participant's sleep latencies between the two nights are mostly fewer than 10 minutes, but for five of the participants, the difference is close to an hour. Would it be valid for the sleep researcher to use the independent-measures & test to test whether playing classical music before going to bed shortens sleep latency? O Yes. No, because the sleep researcher is using a repeated-measures (within-subjects) research design. In this type of design, the study populations are not independent. O No, because she does not have homogeneity of variance. Yes, if her sample size is 230 or the raw scores are normally distributed