In 1954, researchers Gollop and Marshall defined age classes of ducks based on their plumage, from the earliest stages "bright ball of fluff," and "fading ball of fluff," to the next-to-last stage "feathered-flightless," and, finally, "flying."
a. Suppose male mallards at the "featheredflightless" stage have weights (in grams) with mean 864 and standard deviation 100. Find the z-score of a male mallard at this stage that weighs 840 grams.
b. Suppose male mallards at the "flying" stage have weights (in grams) with mean 818 and standard deviation 91. Find the z-score of a male mallard at this stage that weighs 840 grams.
c. If a male mallard weighs 840 grams, is he more likely to be at the "featheredflightless" stage or the "flying" stage? Explain.