ECON 261 Chapter 16 || with 100% correct answers.
What is statistical inference on μ? correct answers Drawing conclusions about a population mean
based on a sample mean.
Using information from a sample to estimate a population parameter value is statistical inference.
Which of the following are three components that would completely specify a confidence
interval? correct answers estimate of the population parameter, the confidence level, and the
margin of error
To obtain a confidence interval, we have to know the estimate of the parameter from the sample,
the confidence level and the margin of error. (We also need to know the population standard
deviation and the sample size, which are contained in the margin of error.)
Consider this confidence interval interpretation: We are 90% confident that the true mean weight
of all black bears is between 344.8 and 361.2 pounds. What needs to be done to fix this
statement? correct answers Nothing needs to be fixed; the interpretation is correct.
The confidence level is given, the parameter is stated correctly and in context, and the interval is
given. This is a correct interpretation of the confidence interval.
The weight of four-ounce bags of cashews packaged in a cashew plant follows a Normal
distribution with a standard deviation of 0.03 ounce. Suppose a random sample of 9 bags is to be
taken from production and the mean weight of the sample is computed. The mean of this sample
will likely be _____________ the population mean. correct answers different from
Because the sample will consist of only a few observations from the population, the sample mean
will likely be different from the population mean.
A confidence interval is of the form: estimate ± ____________. correct answers margin of error
, We add and subtract the margin of error from the sample estimate to get a confidence interval
estimate of a parameter.
Which one of the following is NOT part of a confidence interval for μ? correct answers the
population size
The population size does not affect the confidence interval for μ. The population size does not
matter as long as it is large relative to the sample size.
Using information from a sample to describe a population is called ____________. correct
answers inference
Right. Inference is the process of using information taken from a sample in order to describe a
population.
The 95% confidence interval for the population mean is (___ , 16.7) if x̄ = 15 and the margin of
error is 1.7. correct answers 13.3
A confidence interval is x̄ ± margin of error.
A class survey in a large class for first-year college students asked, "About how many hours do
you study during a typical week?" The mean response of the 463 students was 13.7 hours.
Suppose we know that the study time follows a Normal distribution with standard deviation 7.4
hours in the population of all first-year students at this university. To construct the 99%
confidence interval for the mean study time of all first-year students, we use the formula
x¯±z∗σ/n−√. What is the value of n? correct answers 463
This is the sample size n.
What is statistical inference on μ? correct answers Drawing conclusions about a population mean
based on a sample mean.
Using information from a sample to estimate a population parameter value is statistical inference.
Which of the following are three components that would completely specify a confidence
interval? correct answers estimate of the population parameter, the confidence level, and the
margin of error
To obtain a confidence interval, we have to know the estimate of the parameter from the sample,
the confidence level and the margin of error. (We also need to know the population standard
deviation and the sample size, which are contained in the margin of error.)
Consider this confidence interval interpretation: We are 90% confident that the true mean weight
of all black bears is between 344.8 and 361.2 pounds. What needs to be done to fix this
statement? correct answers Nothing needs to be fixed; the interpretation is correct.
The confidence level is given, the parameter is stated correctly and in context, and the interval is
given. This is a correct interpretation of the confidence interval.
The weight of four-ounce bags of cashews packaged in a cashew plant follows a Normal
distribution with a standard deviation of 0.03 ounce. Suppose a random sample of 9 bags is to be
taken from production and the mean weight of the sample is computed. The mean of this sample
will likely be _____________ the population mean. correct answers different from
Because the sample will consist of only a few observations from the population, the sample mean
will likely be different from the population mean.
A confidence interval is of the form: estimate ± ____________. correct answers margin of error
, We add and subtract the margin of error from the sample estimate to get a confidence interval
estimate of a parameter.
Which one of the following is NOT part of a confidence interval for μ? correct answers the
population size
The population size does not affect the confidence interval for μ. The population size does not
matter as long as it is large relative to the sample size.
Using information from a sample to describe a population is called ____________. correct
answers inference
Right. Inference is the process of using information taken from a sample in order to describe a
population.
The 95% confidence interval for the population mean is (___ , 16.7) if x̄ = 15 and the margin of
error is 1.7. correct answers 13.3
A confidence interval is x̄ ± margin of error.
A class survey in a large class for first-year college students asked, "About how many hours do
you study during a typical week?" The mean response of the 463 students was 13.7 hours.
Suppose we know that the study time follows a Normal distribution with standard deviation 7.4
hours in the population of all first-year students at this university. To construct the 99%
confidence interval for the mean study time of all first-year students, we use the formula
x¯±z∗σ/n−√. What is the value of n? correct answers 463
This is the sample size n.
