BUSI 230 - WEEK 8 TERMINOLOGY PRACTICE EXAM QUESTIONS ANSWERED CORRECTLY LATEST
UPDATE 2026
When estimating a population mean, are you more likely to be correct when you use a point estimate
or an interval estimate? Explain your reasoning. - Answers You are more likely to be correct using an
interval estimate because it is unlikely that a point estimate will exactly equal the population mean.
For the same sample statistics, which level of confidence would produce the widest confidence
interval? Explain your reasoning. - Answers 99%, because as the level of confidence increases, z ꜀
increases.
You construct a 95% confidence interval for a population mean using a random sample. The
confidence interval is 24.9 < μ < 31.5 . Is the probability that μ is in this interval 0.95? Explain. -
Answers No. With 95% confidence, the mean is in the interval (24.9, 31.5).
From a random sample of
46 business days, gold prices had a mean of $1383.85 . Assume the population standard deviation is
$202.30 . This creates a 90% confidence interval for the population mean of left parenthesis $1334.79
comma $1432.91 right parenthesis. Does it seem possible that the population mean could equal the
sample mean exactly? Explain. - Answers It would be very unlikely because the margin of error is large
enough that the odds of selecting an exact value is very low.
From a random sample of
60 new games, the mean price for a new game is $58.01 . Assume the population has a standard
deviation of $49.16 . This creates a 95% confidence interval for the population mean of left
parenthesis 45.57 comma 70.45 right parenthesis. Does it seem likely that the population mean could
be greater than $71? Explain. - Answers No, it does not seem
likely because $71 is greater than the right endpoint of the confidence interval.
How does an increase in the level of confidence affect the width of a confidence interval? Choose the
correct answer below. - Answers An increase in the level of confidence will widen the confidence
interval.
How does an increase in the sample size affect the width of a confidence interval? Choose the correct
answer below. - Answers An increase in the sample size will narrow the confidence interval.
How does an increase in the population standard deviation affect the width of a confidence interval?
Choose the correct answer below. - Answers An increase in the population standard deviation will
widen the confidence interval.
When estimating the population mean, why not construct a 99% confidence interval every time? -
Answers A 99% may produce a CI so wide that it has no practical application.
From a random sample of 60 new games, the mean price for a new game is $58.01 . Assume the
population has a standard deviation of $49.16 . This creates a 95% confidence interval for the
population mean of left parenthesis 45.57 comma 70.45 right parenthesis. Does it seem likely that the
population mean could be greater than $71? Explain. - Answers No, it does not seem likely because
$71 is greater than the right endpoint of the confidence interval.
From a random sample of 46 business days, gold prices had a mean of $1383.85. Assume the
population standard deviation is $202.30. This creates a 90% confidence interval for the population
mean of left parenthesis $1334.79 comma $1432.91 right parenthesis. Does it seem possible that the
population mean could equal the sample mean exactly? Explain. - Answers It would be very unlikely
because the margin of error is large enough that the odds of selecting an exact value is very low.
What do you need to remember when doing math for graphed confidence problems? - Answers The
bigger the confidence value, the bigger the range of the line on the graph.
What formula do we use to find the margin of error E? - Answers E = z ꜀ ( σ / √n )
What z꜀ value is equal to 90%? - Answers 1.645
What z꜀ value is equal to 95%? - Answers 1.96
What z꜀ value is equal to 99%? - Answers 2.575
What equation do we use to find the c-value? - Answers ( 1/2 ) * ( 1 - ꜀ )
After you find the c-value, what do you do? - Answers Plug c-value in NORM.S.INV, and flip the
resulting value from positive to negative (or negative to positive if it is negative first).
What equation do we use to find the minimum sample size? (assmuning that - Answers n = ( ( z ꜀ * σ ) /
E)^2
How do you find the left endpoint of a confidence interval? - Answers x̄ - E
(mean) - (margin of error)
UPDATE 2026
When estimating a population mean, are you more likely to be correct when you use a point estimate
or an interval estimate? Explain your reasoning. - Answers You are more likely to be correct using an
interval estimate because it is unlikely that a point estimate will exactly equal the population mean.
For the same sample statistics, which level of confidence would produce the widest confidence
interval? Explain your reasoning. - Answers 99%, because as the level of confidence increases, z ꜀
increases.
You construct a 95% confidence interval for a population mean using a random sample. The
confidence interval is 24.9 < μ < 31.5 . Is the probability that μ is in this interval 0.95? Explain. -
Answers No. With 95% confidence, the mean is in the interval (24.9, 31.5).
From a random sample of
46 business days, gold prices had a mean of $1383.85 . Assume the population standard deviation is
$202.30 . This creates a 90% confidence interval for the population mean of left parenthesis $1334.79
comma $1432.91 right parenthesis. Does it seem possible that the population mean could equal the
sample mean exactly? Explain. - Answers It would be very unlikely because the margin of error is large
enough that the odds of selecting an exact value is very low.
From a random sample of
60 new games, the mean price for a new game is $58.01 . Assume the population has a standard
deviation of $49.16 . This creates a 95% confidence interval for the population mean of left
parenthesis 45.57 comma 70.45 right parenthesis. Does it seem likely that the population mean could
be greater than $71? Explain. - Answers No, it does not seem
likely because $71 is greater than the right endpoint of the confidence interval.
How does an increase in the level of confidence affect the width of a confidence interval? Choose the
correct answer below. - Answers An increase in the level of confidence will widen the confidence
interval.
How does an increase in the sample size affect the width of a confidence interval? Choose the correct
answer below. - Answers An increase in the sample size will narrow the confidence interval.
How does an increase in the population standard deviation affect the width of a confidence interval?
Choose the correct answer below. - Answers An increase in the population standard deviation will
widen the confidence interval.
When estimating the population mean, why not construct a 99% confidence interval every time? -
Answers A 99% may produce a CI so wide that it has no practical application.
From a random sample of 60 new games, the mean price for a new game is $58.01 . Assume the
population has a standard deviation of $49.16 . This creates a 95% confidence interval for the
population mean of left parenthesis 45.57 comma 70.45 right parenthesis. Does it seem likely that the
population mean could be greater than $71? Explain. - Answers No, it does not seem likely because
$71 is greater than the right endpoint of the confidence interval.
From a random sample of 46 business days, gold prices had a mean of $1383.85. Assume the
population standard deviation is $202.30. This creates a 90% confidence interval for the population
mean of left parenthesis $1334.79 comma $1432.91 right parenthesis. Does it seem possible that the
population mean could equal the sample mean exactly? Explain. - Answers It would be very unlikely
because the margin of error is large enough that the odds of selecting an exact value is very low.
What do you need to remember when doing math for graphed confidence problems? - Answers The
bigger the confidence value, the bigger the range of the line on the graph.
What formula do we use to find the margin of error E? - Answers E = z ꜀ ( σ / √n )
What z꜀ value is equal to 90%? - Answers 1.645
What z꜀ value is equal to 95%? - Answers 1.96
What z꜀ value is equal to 99%? - Answers 2.575
What equation do we use to find the c-value? - Answers ( 1/2 ) * ( 1 - ꜀ )
After you find the c-value, what do you do? - Answers Plug c-value in NORM.S.INV, and flip the
resulting value from positive to negative (or negative to positive if it is negative first).
What equation do we use to find the minimum sample size? (assmuning that - Answers n = ( ( z ꜀ * σ ) /
E)^2
How do you find the left endpoint of a confidence interval? - Answers x̄ - E
(mean) - (margin of error)
