The number of training hours that a student must accumulate before mastering a complex statistical software varies from 10 to 15, depending on the student's comprehension skills. After several years of offering this training, Dr. Smith developed a probability distribution that describes the proportion of the users mastering the software after each training hour. Use the information in the table below to calculate the median number of training hours necessary to master the software. X P(x 10 D. 1 11 0.25 12 0.4 13 0.48 14 0.32 15 0.24 O 75 O 13 O 12.5 O 15