stats chapter 8 Exam Questions Answered Correctly Graded A+
a 95% confidence interval for the population mean implies that - Answers for repeated sample, 95% of
the sample means will fall within the interval
a confidence interval narrows if the following is accomplished - Answers The sample size increases
The chosen confidence level decreases
the sampling distribution of the estimator x- follows a normal distribution when the underlying
population follows a _____ distribution - Answers normal
a sample of 25 is drawn for a normal population with an unknown population SD. The sample mean and
the sample SD are calculated as 35 and 100, respectively. For a 95% confidence interval z0.025 and
t0.025,24 = 2.064. A 95% confidence interval for the population mean is equal to - Answers 35 +-
2.064(100/sq rt5)
table lists t df values for selected upper-tail probabilities and degrees of freedom. If df=6 and a=0.05,
find t a,df - Answers 1.943
T/F: a confidence interval provides a range of values that should contain a population parameter with a
certain level of confidence - Answers true
in order to construct a confidence interval for u, the sampling distribution of the estimator x- must
follow a ____ distribution - Answers normal
a sample of 25 is drawn from a normal population. A sample mean of 50 is calculated. For a 95%
confidence interval, the margin of error is 10. A 95% confidence interval for the mean is - Answers 50 +-
10
a 100(1-a)% confidence interval for the population proportion is - Answers p' +- z a/2 *sq rt p'(1-p')/n
the parameter p represents the - Answers population proportion
the most practical way to reduce the margin of error is to - Answers increase the sample size
when the population SD is unknown, the standard error for the sample mean is calculated as - Answers s
/ sqrt n
a 95% confidence interval for the population mean is constructed as 6 +- 2. What is the probability of
error, a? - Answers 0.05
suppose you are constructing a confidence interval for the population mean. For a given confidence
level and SD, the width of the interval is wider for a - Answers smaller sample size
when the confidence level increases from 95% to 99%, the confidence interval for the population mean -
Answers widens
a 95% confidence interval for the population mean implies that - Answers for repeated sample, 95% of
the sample means will fall within the interval
a confidence interval narrows if the following is accomplished - Answers The sample size increases
The chosen confidence level decreases
the sampling distribution of the estimator x- follows a normal distribution when the underlying
population follows a _____ distribution - Answers normal
a sample of 25 is drawn for a normal population with an unknown population SD. The sample mean and
the sample SD are calculated as 35 and 100, respectively. For a 95% confidence interval z0.025 and
t0.025,24 = 2.064. A 95% confidence interval for the population mean is equal to - Answers 35 +-
2.064(100/sq rt5)
table lists t df values for selected upper-tail probabilities and degrees of freedom. If df=6 and a=0.05,
find t a,df - Answers 1.943
T/F: a confidence interval provides a range of values that should contain a population parameter with a
certain level of confidence - Answers true
in order to construct a confidence interval for u, the sampling distribution of the estimator x- must
follow a ____ distribution - Answers normal
a sample of 25 is drawn from a normal population. A sample mean of 50 is calculated. For a 95%
confidence interval, the margin of error is 10. A 95% confidence interval for the mean is - Answers 50 +-
10
a 100(1-a)% confidence interval for the population proportion is - Answers p' +- z a/2 *sq rt p'(1-p')/n
the parameter p represents the - Answers population proportion
the most practical way to reduce the margin of error is to - Answers increase the sample size
when the population SD is unknown, the standard error for the sample mean is calculated as - Answers s
/ sqrt n
a 95% confidence interval for the population mean is constructed as 6 +- 2. What is the probability of
error, a? - Answers 0.05
suppose you are constructing a confidence interval for the population mean. For a given confidence
level and SD, the width of the interval is wider for a - Answers smaller sample size
when the confidence level increases from 95% to 99%, the confidence interval for the population mean -
Answers widens
