Question 5.83

53. Bigger animals tend to carry their young longer before birth. The length of horse pregnancies from conception to birth varies according to a roughly normal distribution, with a mean of 336 days and a standard deviation of 3 days. Use the 68-95-99.7 rule to answer the following questions.

  1. Almost all (99.7%) horse pregnancies fall in what interval of lengths?
  2. What percentage of horse pregnancies is longer than 339 days?

53.

(a) , or 327 to 345 days

(b) 16% lie above 339.

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