[2008] Topic 6: Statistical Inference: Estimation and Hypothesis Testing 相关 important, describes, summarize, following

leiyou

 

AIM 1: Define the concept of statistical inference.

1、 Which one of the following alternatives best describes the primary use of inferential statistics? Inferential statistics are used to:

A) approximate the characteristics of any data set.

B) make forecasts based on large data sets.

C) summarize the important characteristics of a large data set based on statistical characteristics of a smaller sample.

D) make forecasts, estimates or judgments about a large set of data based on statistical characteristics of a smaller sample

leiyou

 

The correct answer is D

Inferential statistics are used mainly to make forecasts, estimates or judgements about a large set of data based on statistical characteristics of a smaller set of data.

leiyou

 

AIM 2: Define and distinguish between estimator and parameterfficeffice" />

1、Which of the following statements regarding the terms population and sample is least accurate?

A) Observing all members of a population can be expensive or time consuming.

B) A sample includes all members of a specified group.

C) A sample's characteristics are attributed to the population as a whole.

D) A descriptive measure of a sample is called a statistic.

leiyou

 

The correct answer is B

A population includes all members of a specified group. A sample is a portion, or subset of the population of interest.

leiyou

 

2、Which of the following statements about statistical concepts is least accurate?

A) A frequency distribution is a tabular display of data summarized into a relatively small number of intervals.

B) An interval is a set of return values within which an observation falls.

C) A sample contains all members of a specified group, but a population contains only a subset.

D) A parameter is any descriptive measure of a population characteristic.

leiyou

 

The correct answer is C

A population is defined as all members of a specified group, but a sample is a subset of a population.

leiyou

 

AIM 3: Define and distinguish between point estimate, estimation interval.

1、Which of the following statements about sampling and estimation is most accurate?

A) The standard deviation of the distribution of the sample means is the standard error of the residual.

B) The standard error of the sample means when the standard deviation of the population is unknown equals s / √n, where s = sample standard deviation.

C) The standard error of the sample means when the standard deviation of the population is known equals σ / √n, where σ = sample standard deviation adjusted by n ? 1.

D) The probability that a parameter lies within a range of estimated values is given by α.

leiyou

 

The correct answer is B

The probability that a parameter lies within a range of estimated values is given by 1 ? σ. The standard deviation of the distribution of the sample means is the standard error of the sample mean. The term residual is used during the discussion of regression that occurs later in this study session. The standard error of the sample means when the standard deviation of the population is known equals σ / √n, where σ = population standard deviation.

leiyou

 

2、A range of estimated values within which the actual value of a population parameter will lie with a given probability of 1 ? α is a(n):

A) α percent point estimate.

B) (1 ? α) percent confidence interval.

C) α percent confidence interval.

D) (1 ? α) percent cross-sectional point estimate.

leiyou

 

The correct answer is B

A 95% confidence interval for the population mean (α = 5% is the p-value), for example, is a range of estimates within which the actual value of the population mean will lie with a probability of 95%. Point estimates, on the other hand, are single (sample) values used to estimate population parameters. There is no such thing as a α% point estimate or a (1 ? α)% cross-sectional point estimate.