BAN 280: Key Concepts for the Final
If we have a normal population, and we draw all samples of size 5 from this population, what shape will
the sampling distribution of sample means be according to the Central Limit Theorem?
a) skewed
b) cannot say
c) normal
d) t-distribution - correct answer ✔✔normal
The statistic x bar is the point estimator of
a) mu
b) sigma
c) beta
d) alpha - correct answer ✔✔mu
The standard deviation of the sampling distribution is called the
a) sampling error
b) margin of error
c) standard error
d) sample standard deviation - correct answer ✔✔standard error
As the sample size increases, the standard error of the mean
a) also increases
b) decreases
c) stays the same
d) depends on the confidence level - correct answer ✔✔decreases
Time spent by office workers using email per session is normally distributed with a mean, mu, of 8
minutes and a standard deviation, sigma, of 2 minutes. A random sample of 25 workers was selected.
, What is the standard error of the mean?
a) 0.4
b) 0.08
c) 1.6
d) 0.32 - correct answer ✔✔0.4
Time spent by office workers using email per session is normally distributed with a mean, mu, of 8
minutes and a standard deviation, sigma, of 2 minutes. A random sample of 25 workers was selected.
What is the probability that the average time spent reading email for this sample is more than 7.5
minutes?
a) 0.3944
b) 0.0987
c) 0.8944
d) 0.50987 - correct answer ✔✔0.8944
In confidence intervals, a change in sample size (while keeping other values constant) results in a change
in the
a) sample mean
b) population mean
c) confidence level
d) margin of error - correct answer ✔✔margin of error
You are given that a 99% confidence interval for a population mean is (12,28). The sample mean used to
construct this confidence interval was
a) 15
b) 20
c) cannot say without the margin of error
d) cannot say without the sample size - correct answer ✔✔20
If we have a normal population, and we draw all samples of size 5 from this population, what shape will
the sampling distribution of sample means be according to the Central Limit Theorem?
a) skewed
b) cannot say
c) normal
d) t-distribution - correct answer ✔✔normal
The statistic x bar is the point estimator of
a) mu
b) sigma
c) beta
d) alpha - correct answer ✔✔mu
The standard deviation of the sampling distribution is called the
a) sampling error
b) margin of error
c) standard error
d) sample standard deviation - correct answer ✔✔standard error
As the sample size increases, the standard error of the mean
a) also increases
b) decreases
c) stays the same
d) depends on the confidence level - correct answer ✔✔decreases
Time spent by office workers using email per session is normally distributed with a mean, mu, of 8
minutes and a standard deviation, sigma, of 2 minutes. A random sample of 25 workers was selected.
, What is the standard error of the mean?
a) 0.4
b) 0.08
c) 1.6
d) 0.32 - correct answer ✔✔0.4
Time spent by office workers using email per session is normally distributed with a mean, mu, of 8
minutes and a standard deviation, sigma, of 2 minutes. A random sample of 25 workers was selected.
What is the probability that the average time spent reading email for this sample is more than 7.5
minutes?
a) 0.3944
b) 0.0987
c) 0.8944
d) 0.50987 - correct answer ✔✔0.8944
In confidence intervals, a change in sample size (while keeping other values constant) results in a change
in the
a) sample mean
b) population mean
c) confidence level
d) margin of error - correct answer ✔✔margin of error
You are given that a 99% confidence interval for a population mean is (12,28). The sample mean used to
construct this confidence interval was
a) 15
b) 20
c) cannot say without the margin of error
d) cannot say without the sample size - correct answer ✔✔20
