MATH221 Week 5 Quiz| Questions & Answers
(Complete Solutions 100% Correct)
Determine the minimum sample size required when you want to be 80% confident that
the sample mean is within 1.5 units of the population mean. Assume a standard
deviation of 9.24 in a normally distributed population. - ✔✔63
Determine the minimum sample size required when you want to be 75% confident that
the sample mean is within thirty units of the population mean. Assume a standard
deviation of 327.8 in a normally distributed population - ✔✔158
In a sample of 8 high school students, they spent an average of 28.8 hours each week
doing sports with a standard deviation of 3.2 hours. Find the 95% confidence interval. -
✔✔(26.12, 31.48)
In a sample of 15 stuffed animals, you find that they weigh an average of 8.56 ounces
with a standard deviation of 0.08 ounces. Find the 92% confidence interval. -
✔✔(8.521, 8.599)
Market research indicates that a new product has the potential to make the company
an additional $3.8 million, with a standard deviation of $1.7 million. If this estimate was
based on a sample of 10 customers, what would be the 90% confidence interval? -
✔✔(2.81, 4.79)
A heated election is coming up where people will select the all-time favorite cartoon.
We take a poll before the election to see how the race is shaping up. According to this
poll, 34% of the people say they will vote for Bugs Bunny and 26% say they will vote for
Baby Shark. The poll has an error of +/-2 %. Based on this result, can one say that in the
population, more people clearly support Bugs Bunny over Baby Shark? - ✔✔Yes, as
the confidence intervals for the two groups do not overlap
, In a sample of 17 small candles, the weight is found to be 3.72 ounces with a standard
deviation of 0.963 ounces. What would be the 87% confidence interval for the size of
the candles? - ✔✔(3.347, 4.093)
In a situation where the standard deviation was decreased from 5.8 to 3.1, what would
be the impact on the confidence interval? - ✔✔It would become narrower due to the
change in standard deviation
In a random sample of eighteen people, the mean time at lunch was 28.4 minutes with a
standard deviation of 8.2 minutes. Assuming the data are normally distributed, what
would be the 85% confidence interval? - ✔✔(25.49, 31.31)
If a confidence interval is known to be (56.28, 62.72), what would be its margin of error?
- ✔✔3.22
A company manufacturers soda cans with a diameter of 52 millimeters. In a sample of
12 cans, the standard deviation was 2.3 millimeters. What would be the 96% confidence
interval for these cans? - ✔✔(50.45, 53.55)
From a random sample of 68 businesses, it is found that the mean time that employees
spend on personal issues each week is 4.9 hours with a standard deviation of 0.35
hours. What is the 95% confidence interval for the amount of time spent on personal
issues? - ✔✔(4.82, 4.98)
If the population standard deviation of a sample decreases without other changes, what
is most likely to happen to the confidence interval? - ✔✔narrows
From a random sample of 41 teens, it is found that on average they spend 31.8 hours
each week online with a population standard deviation of 3.65 hours. What is the 90%
(Complete Solutions 100% Correct)
Determine the minimum sample size required when you want to be 80% confident that
the sample mean is within 1.5 units of the population mean. Assume a standard
deviation of 9.24 in a normally distributed population. - ✔✔63
Determine the minimum sample size required when you want to be 75% confident that
the sample mean is within thirty units of the population mean. Assume a standard
deviation of 327.8 in a normally distributed population - ✔✔158
In a sample of 8 high school students, they spent an average of 28.8 hours each week
doing sports with a standard deviation of 3.2 hours. Find the 95% confidence interval. -
✔✔(26.12, 31.48)
In a sample of 15 stuffed animals, you find that they weigh an average of 8.56 ounces
with a standard deviation of 0.08 ounces. Find the 92% confidence interval. -
✔✔(8.521, 8.599)
Market research indicates that a new product has the potential to make the company
an additional $3.8 million, with a standard deviation of $1.7 million. If this estimate was
based on a sample of 10 customers, what would be the 90% confidence interval? -
✔✔(2.81, 4.79)
A heated election is coming up where people will select the all-time favorite cartoon.
We take a poll before the election to see how the race is shaping up. According to this
poll, 34% of the people say they will vote for Bugs Bunny and 26% say they will vote for
Baby Shark. The poll has an error of +/-2 %. Based on this result, can one say that in the
population, more people clearly support Bugs Bunny over Baby Shark? - ✔✔Yes, as
the confidence intervals for the two groups do not overlap
, In a sample of 17 small candles, the weight is found to be 3.72 ounces with a standard
deviation of 0.963 ounces. What would be the 87% confidence interval for the size of
the candles? - ✔✔(3.347, 4.093)
In a situation where the standard deviation was decreased from 5.8 to 3.1, what would
be the impact on the confidence interval? - ✔✔It would become narrower due to the
change in standard deviation
In a random sample of eighteen people, the mean time at lunch was 28.4 minutes with a
standard deviation of 8.2 minutes. Assuming the data are normally distributed, what
would be the 85% confidence interval? - ✔✔(25.49, 31.31)
If a confidence interval is known to be (56.28, 62.72), what would be its margin of error?
- ✔✔3.22
A company manufacturers soda cans with a diameter of 52 millimeters. In a sample of
12 cans, the standard deviation was 2.3 millimeters. What would be the 96% confidence
interval for these cans? - ✔✔(50.45, 53.55)
From a random sample of 68 businesses, it is found that the mean time that employees
spend on personal issues each week is 4.9 hours with a standard deviation of 0.35
hours. What is the 95% confidence interval for the amount of time spent on personal
issues? - ✔✔(4.82, 4.98)
If the population standard deviation of a sample decreases without other changes, what
is most likely to happen to the confidence interval? - ✔✔narrows
From a random sample of 41 teens, it is found that on average they spend 31.8 hours
each week online with a population standard deviation of 3.65 hours. What is the 90%
