Exam 10: Introduction to Estimation

The larger the confidence level,the:

College Dean A college dean would like to estimate a population mean to within 40 units with 99% confidence given that the population standard deviation is 200. ​ ​ -{College Dean Narrative} What sample size should be used if using a 95% confidence level?

An interval estimator estimates the value of an unknown ____________________.

The letter α in the formula for constructing a confidence interval estimate of the population mean is:

Conference Rooms Rented A hotel chain wants to estimate the average number of conference rooms rented daily in each month.The population of conference rooms rented daily is assumed to be normally distributed for each with a standard deviation of 24 rooms. ​ ​ -{Conference Rooms Rented Narrative} During February,a sample of 25 days has a sample mean of 37 rooms.Use this information to calculate a 92% confidence interval for the population mean.

If you increase the confidence level,the confidence interval becomes ____________________.

The bound on the error of estimation is the ____________________ amount of sampling error that we are willing to tolerate.

Because n is an integer and we want the bound on the error of estimation to be no more than a given amount,any non-integer value found for n must always be rounded ____________________.

In the formula ,the α / 2 refers to:

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} Determine the 95% confidence interval estimate of the population mean.

We cannot interpret the confidence interval estimate of μ as a probability statement about μ because the population mean is a fixed quantity.

To estimate the mean of a normal population whose standard deviation is 6,with a bound on the error of estimation equal to 1.2 and confidence level 99% requires a sample size of at least:

A point estimator is defined as:

The sample size needed to estimate a population mean within 2 units with a 95% confidence when the population standard deviation equals 8 is

In developing an interval estimate for a population mean,a sample of 50 observations was used.The interval estimate was 19.76 ± 1.32.Had the sample size been 200 instead of 50,the interval estimate would have been:

How large a sample of federal employees in Nevada should be taken if we want to estimate with 98% confidence the mean salary to within $2,000.The population standard deviation is assumed to be $10,500.

If the population values are very close to each other,the width of the confidence interval is ____________________ than if the population values are very far apart.

One can reduce the width of a confidence interval by taking a smaller sample size.

When constructing confidence interval estimate of μ,doubling the sample size n decreases the width of the interval by half.

The value for a 95% confidence interval estimate for a population mean μ is