Pitch memory of amusiacs. Refer to the Advances in Cognitive Psychology (Vol. 6, 2010) study of pitch memory of amusiacs, Exercise 7.45

(p. 363). Recall that diagnosed amusiacs listened to a series of tone pairs and were asked to determine if the tones were the same or different.

In the first trial, the tones were separated by 1 second; in the second trial, the tones were separated by 5 seconds.

The variable of interest was the difference between scores on the two trials. How many amusiacs would need to participate in the study in order to estimate the true mean score difference for all amusiacs to within .05 with 90%

confidence?