In the Southern Ocean food web, the krill species Euphausiasuperba is the most important prey species for many marinepredators, from seabirds to the largest whales. Body lengths of thespecies are normally distributed with a mean of 40 mm and astandard deviation of 12 mm. (a) What is the probability that arandomly selected krill is longer than 46 mm? (b) Describe thedistribution of the mean length of a sample of four krill. (c) Whatis the probability that the mean length of a sample of four krillis more than 46 mm? (d) Could you estimate the probabilities fromparts (a) and (c) if the lengths of krill had a skeweddistribution?
