Exam 10: Introduction to Estimation

A financial consultant wanted to determine the mean annual return on Bond funds.A random sample of 60 returns shows a mean of 12%.If the population standard deviation is assumed to be 4%,estimate with 95% confidence the mean annual return on all Bond funds.

Draw sampling distributions of a consistent estimator for μ where one sample mean is larger than the other.

An economist is interested in studying the spending habits of consumers in a particular region.The population standard deviation is known to be $1,000.A random sample of 50 individuals resulted in an average expense of $15,000.What is the width of the 99% confidence interval?

Which of the following statements is true?

A market researcher is interested in studying the incomes of consumers in a particular region.The population standard deviation is known to be $1,000.A random sample of 50 individuals resulted in an average income of $15,000.What is the upper end point in a 99% confidence interval for the average income?

An unbiased estimator is a sample statistic whose expected value equals the population parameter.

An unbiased estimator is said to be consistent if the difference between the estimator and the parameter grows smaller as the sample size grows larger.

An unbiased estimator has an average value (across all samples)equal to the population parameter.

Knowing that an estimator is unbiased only assures us that its expected value equals the parameter,but it does not tell us how close the estimator is to the parameter.

The sampling error for a confidence interval is also defined as the ____________________ of ____________________.

Time Spent Playing Computer Games Suppose that the amount of time teenagers spend playing computer games per week is normally distributed with a standard deviation of 1.5 hours.A sample of 100 teenagers is selected at random,and the sample mean computed as 6.5 hours. ​ ​ -{Time Spent Playing Computer Games Narrative} Interpret the 95% confidence interval for this situation.

If there are two unbiased estimators of a parameter,the one whose variance is smaller is said to be relatively efficient.

Increasing the value of 1 − α narrows a confidence interval.

A confidence interval is a probability statement about the ____________________ mean.

The sample variance is a point estimate of the population variance.

When estimating the population mean using a confidence interval,the sample mean is in the ____________________ of the interval.

The population mean is a(n)____________________ but ____________________ quantity.

A point estimate consists of a single sample statistic that is used to estimate the true population parameter.

The difference between the sample statistic and actual value of the population parameter is the confidence level of the estimate.

A confidence interval is an interval estimate for which there is a specified degree of certainty that the actual value of the population parameter will fall within the interval.