Ch.9 Business Statistics
In terms of the standard error of the mean, how wide is a 90 percent confidence interval?
2.29 Standard errors
Increasing sample size provides a more _____ of a population parameter
Accurate
What is the interval withing which a population parameter is expected to lie
Confidence interval
A confidence interval is narrower when the standard deviation ______
Decreases
What is the probability that an interval estimate include the population parameter
Degree or level of confidence
A confidence interval for a population proportion is based on using the uniform distribution to approximate the binomial distribution.
False
A point estimate is a range of values used to estimate a population parameter
False
A sample of 2000 union members was selected and their opinions regarding a proposed management union contract were recorded. 1600 members were in favor of it. A 95% confidence interval for the population proportion was computed to be 0.78 and 0.82. This indicates that about 80 out of 100 similarly constructed intervals would include the population proportion
False
An interval estimate is a singe value used to estimate a population parameter
False
An interval estimate is singe value used to estimate a population parameter
False
The finite population correction factor is used to adjust the z-statistic
False
The population variation as measured by the standard deviation has little or no effect in determining the size of a sample selected from the population
False
The statistic for a problem involving any sample size and an unknown population standard deviation is the z distribution
False
The test statistic for a problem involving any sample size and an unknown population standard deviation is the z distribution
False
The test statistic for a problem involving any sample size and an unknown population standard deviation is the z-distribution
False
To determine the value of the standard error of the mean, the total error is divided by the sample size.
False
What type of estimate states the range within which a population parameter probably lies?
Interval estimate
Other things being equal a smaller sample size would result in a wider confidence interval because the standard error of the mean is_______
Larger
To calculate the sample size required to estimate a population mean, smaller margins of error require _____ sample sizes
Larger
A sample mean is a ______ of the population mean
Point Estimate
A sample mean is a _______ of the population mean
Point estimate
A 95 percent confidence interval implies that about 95 out of 100 similarly constructed intervals will include the ______ being estimated
Population parameter or parameter
To calculate the sample size required to estimate a population mean, we must know or estimate the ________ of the population distribution
Standard Deviation
What does the t distribution approach as the sample size increases?
Standard normal Z distribution
Making generalized statements about a population based on a sample is called
Statistical inference
To compute a confidence interval, a _____ is used when the population standard deviation is unknown
T-statistic
A 95% confidence interval states that 95% of the sample means of a specified sample size selected from a population will lie within plus or minus 1.96 standard deviations of the hypothesized population mean
True
A point estimate is a singe value used to estimate a population parameter
True
An interval estimate is a range of values used to estimate a population parameter
True
One factor in determining the size of a sample is the degree of confidence selected. This is usually 0.95 or 0.99, but it may be any degree of confidence you specify
True
The finite population correction factor is applied when the population size is known
True
The t distribution is based on the assumption that the population of interest is normal or nearly normal
True
To determine the size of a sample. the standard deviation of the population must be estimated by either taking a pilot survey or by approximation is based on knowing the population
True
A confidence interval is narrower when the sample size
increases
In order to construct the 68% confidence interval, how many standard errors of the mean from the hypothesized population mean must you go?
1, or plus or minus 1 standard error
To compute a confidence interval, a ______ Is used when the population standard deviation is known.
z-statistic