答案和详解如下： 1.With 60 observations, what is the appropriate number of degrees of freedom to use when carrying out a statistical test on the mean of a population? A) 61. B) 60. C) 58. D) 59. The correct answer was D) When performing a statistical test on the mean of a population based on a sample of size n, the number of degrees of freedom is n – 1 since once the mean is estimated from a sample there are only n – 1 observations that are free to vary. In this case the appropriate number of degrees of freedom to use is 60 – 1 = 59. 2.Which one of the following distributions is described entirely by the degrees of freedom? A) Normal distribution. B) Student’s t-distribution. C) Binomial distribution. D) Lognormal distribution. The correct answer was B) Student’s t-distribution is defined by a single parameter known as the degrees of freedom. | 
发表于 2008-4-14 14:54
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