Refer to the Acoustical Science & Technology (Vol. 35, 2014) study of the degree to which the memorization process is impaired by irrelevant background speech (called irrelevant speech effects), Exercise 2.34 (p. 49). Recall that subjects performed a memorization task under two conditions: (1) with irrelevant background speech and (2) in silence. Let x represent the difference in the error rates for the two conditions-called the relative difference in error rate (RDER). Explain why x is a continuous random variable.