Ch 10 Stats
A 90% confidence interval estimate of the population mean can be interpreted to mean that: a. if we repeatedly draw samples of the same size from the same population, 90% of the values of the sample means will result in a confidence interval that includes the population mean . b. there is a 90% probability that the population mean will lie between the lower confidence limit (LCL) and the upper confidence limit (UCL). c. we are 90% confident that we have selected a sample whose range of values does not contain the population mean . d. We are 90% confident that 10% the values of the sample means will result in a confidence interval that includes the population mean .
a
An unbiased estimator is: A) a sample statistic, which has an expected value equal to the value of the population parameter B) any sample statistic used to approximate a population parameter C) a sample statistic, which is usually less than the population parameter D) any standard error of the sample mean
a
Which of the following factors do not affect the margin of error? A) Sample mean B) Population variance C) Sample size D) Confidence level
a
Which of the following is NOT a characteristic for a good estimator? a. Biasedness b. Consistency c. Relative efficiency d. Unbiasedness
a
If there are two unbiased estimators of a population parameter, the one whose variance is smaller is said to be: a. a biased estimator b. relatively efficient c. consistent d. relatively unbiased
b
The term 1- (alpha) refers to: a. the probability that a confidence interval does not contain the population parameter b. the confidence level c. the level of unbiasedness d. the level of consistency
b
. In the formula , the alpha refers to: a. the probability that the confidence interval will contain the population mean b. the probability that the confidence interval will not contain the population mean c. the area in the lower tail or upper tail of the sampling distribution of the sample mean d. the level of confidence
c
A 98% confidence interval estimate for a population mean is determined to be 75.38 to 86.52. If the confidence level is reduced to 90%, the confidence interval for a. becomes wider b. remains the same c. becomes narrower d. None of the above.
c
A point estimate is defined as: a. the average of the sample values b. the average of the population values c. a single value that is the best estimate of an unknown population parameter d. a single value that is the best estimate of an unknown sample statistic
c
The letter alpha in the formula for constructing a confidence interval estimate of the population mean is a. the level of confidence b. the probability that a confidence interval will contain the population mean c. the probability that a confidence interval will not contain the population mean d. the area in the lower tail of the sampling distribution of the sample mean
c