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.

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.

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.