The Survey of Earned Doctorates published by Statistics Canada revealed that doctoral candidates required, on average, 68 months to earn their Ph.D. degrees. If time to completion is normally...

Extracted text: The Survey of Earned Doctorates published by Statistics Canada revealed that doctoral candidates required, on average, 68 months to earn their Ph.D. degrees. If time to completion is normally distributed with a standard deviation of 13 months, find the probability that a doctoral candidate will earn a Ph.D. degree in: (Round to 4 decimals) a. Less than 5 years. b. Between 5 and 6 years. c. More than 5.5 years. d. More than 6 years. e. Between 4.5 and 5.5 years.