Final answer:
Calculate the probabilities associated with the duration of animal pregnancies using normal distribution and z-scores.
Step-by-step explanation:
The normal distribution of pregnancy lengths in animals and involves calculating probabilities and z-scores. Given a mean of 280 days and a standard deviation of 13 days for pregnancy duration, we can calculate the probability that the father was not present during the conception period if the pregnancy lasts less than 240 days or more than 306 days.
To find these probabilities, we must first calculate the z-scores associated with each of these durations and then, using a standard normal distribution table or a calculator, determine the probabilities that correspond to these z-scores. This exercise is an example of a standard statistical analysis using normal distribution models, which are commonly encountered in the field of statistics.