Pregnancy length in horses. Bigger mammals tend to carry their young longer before giving birth. The length of horse pregnancies from conception to birth varies according to a roughly Normal distribution, with mean 336 days and standard deviation 3 days. Use the 68–95–99.7 rule to answer the following questions. Required:What percent of horse pregnancies are longer than 339 days?

  16%

Step-by-step explanation:

The difference between the time of interest (339 days) and the mean (336 days) is 3 days, which is exactly 1 standard deviation.

The 68-95-99.7 rule tells you that 68% of pregnancies will be within 1 standard deviation. The remaining 32% will be evenly split between pregnancies that are longer than 339 days and ones that are shorter than 333 days. So, half of 32%, or 16%, will be longer than 339 days.

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step-by-step explanation: