1. The arithmetic mean and standard deviation of a certain normal distribution are 13.5 and 1.5, respectively, what value is exactly 2 standard deviations less than the mean?
A) 10.5 B) 11.0 C) 11.5 D)12.0 E) 12.5
answer is A)
2. Five pieces of wood have an average (arithmetic mean) length of 124cm, and a median leghth of 140cm. What is the maxium poosible length, in centimeters, of the shortest piece of wood?
2, (a+b+c+d+e)/5=124, respectly, c=140, then if hope a(the shortest piece of wood)is maxium, then d and e must as short as possible d=e=140, then a=b=100
以下是引用floridaus在2006-10-23 11:04:00的发言： 2, (a+b+c+d+e)/5=124, respectly, c=140, then if hope a(the shortest piece of wood)is maxium, then d and e must as short as possible d=e=140, then a=b=100
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发表于 2006-10-23 08:56:00
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