math question plz plz help
2007-10-11 8:27 pm
the distribution of weights of melons on a certain farm is approximately normally distributed with mean 3kg. if 21% of the melons weigh less than 2.19kg, what % of the crop weighs more than 5 kg?
回答 (1)
2007-10-12 6:57 am
✔ 最佳答案
First, we find out the standard deviation (SD):Standard score, Z (50%-21% i.e. 29%)corresponds to melon weight less than 2.19 kg is -0.805
Therefore, (2.19-3)/SD = -0.8005 and SD = 1.01
Percentage of weight more than 5kg =Probability[(Z>(5-3)/1.01
=Probability (Z>1.98)
=0.5- 0.4761
=0.0239
=2.39%
收錄日期: 2021-04-13 13:52:36
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