Page 1 of 35
BUAL 2650 Gupta FINAL Exam 1 ALL
Questions and Verified Solutions
Latest Update This Year
Consider the trash bag problem. Suppose that an independent laboratory has tested trash
bags and has found that no 30-gallon bags that are currently on the market have a mean
breaking strength of 50 pounds or more. On the basis of these results, the producer of the
new, improved trash bag feels sure that its 30-gallon bag will be the strongest such bag on
the market if the new trash bag’s mean breaking strength can be shown to be at least 50
pounds. The mean of the sample of 39 trash bag breaking strengths in Table 1.10 is x¯=
50.573. If we let µdenote the mean of the breaking strengths of all possible trash bags of the
new type and assume that σ equals 1.61:
Calculate 95 percent confidence intervals for µ. (Round your answers to 3 decimal places.)
[50.068, 51.078]
Consider the trash bag problem. Suppose that an independent laboratory has tested trash
bags and has found that no 30-gallon bags that are currently on the market have a mean
breaking strength of 50 pounds or more. On the basis of these results, the producer of the
new, improved trash bag feels sure that its 30-gallon bag will be the strongest such bag on
the market if the new trash bag’s mean breaking strength can be shown to be at least 50
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pounds. The mean of the sample of 39 trash bag breaking strengths in Table 1.10 is x¯=
50.573. If we let µ denote the mean of the breaking strengths of all possible trash bags of the
new type and assume that σ equals 1.61:
Using the 95 percent confidence interval, can we be 95 percent confident that µ is at least 50
pounds?
Yes, because 95% interval is above 50
Recall that a bank manager has developed a new system to reduce the time customers spend
waiting to be served by tellers during peak business hours. The mean waiting time during
peak business hours under the current system is roughly 9 to 10 minutes. The bank manager
hopes that the new system will have a mean waiting time that is less than six minutes. The
mean of the sample of 91 bank customer waiting times is x¯= 5.41. If we let µdenote the
mean of all possible bank customer waiting times using the new system and assume
that σ equals 2.42:
Calculate 99 percent confidence intervals for µ. (Round your answers to 3 decimal places.)
[4.757, 6.063]
Recall that a bank manager has developed a new system to reduce the time customers spend
waiting to be served by tellers during peak business hours. The mean waiting time during
peak business hours under the current system is roughly 9 to 10 minutes. The bank manager
hopes that the new system will have a mean waiting time that is less than six minutes. The
mean of the sample of 91 bank customer waiting times is x¯= 5.41. If we let µdenote the
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mean of all possible bank customer waiting times using the new system and assume
that σ equals 2.42:
Using the 99 percent confidence interval, can the bank manager be 99 percent confident
that µ is less than six minutes? Explain.
No, the 99% interval extends above mean 6
The mean and the standard deviation of the sample of 100 bank customer waiting times are
x¯= 5.01 and s = 2.116.
Calculate a t-based 95 percent confidence interval for µ, the mean of all possible bank
customer waiting times using the new system. (Choose the nearest degree of freedom for the
given sample size. Round your answers to 3 decimal places.)
[4.590, 5.430]
The value of the test statistic is compared with a(n) ________ in order to decide whether the
null hypothesis can be rejected.
critical value
The area under the normal curve between z = 0 and z = 1 is ________ the area under the
normal curve between z = 1 and z = 2.
greater than
Which of the following is not continuous probability distributions?
binominal
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, Page 4 of 35
If [a,b] denotes an arbitrary interval of numbers on the real number line, Find the probability
when P(x = a)
0
Suppose that we will randomly select a sample of 64 measurements from a population having
a mean equal to 20 and a standard deviation equal to 4.
Describe the shape of the sampling distribution of the sample mean x.
normally distributed
Suppose that we will randomly select a sample of 64 measurements from a population having
a mean equal to 20 and a standard deviation equal to 4. Find the mean and the standard
deviation of the sampling distribution of the sample mean x . (Round your answer to 1
decimal place.)
mean = 20 standard deviation = .5
Suppose that we will randomly select a sample of 64 measurements from a population having
a mean equal to 20 and a standard deviation equal to 4. Calculate the probability that we will
obtain a sample mean greater than 21; that is, calculate P(x> 21). Hint: Find the z value
corresponding to 21 by using and because we wish to calculate a probability about x. (Use the
rounded standard error to compute the rounded Z-score used to find the probability. Round
your answer to 4 decimal places. Round z-scores to 2 decimal places.)
0
4
BUAL 2650 Gupta FINAL Exam 1 ALL
Questions and Verified Solutions
Latest Update This Year
Consider the trash bag problem. Suppose that an independent laboratory has tested trash
bags and has found that no 30-gallon bags that are currently on the market have a mean
breaking strength of 50 pounds or more. On the basis of these results, the producer of the
new, improved trash bag feels sure that its 30-gallon bag will be the strongest such bag on
the market if the new trash bag’s mean breaking strength can be shown to be at least 50
pounds. The mean of the sample of 39 trash bag breaking strengths in Table 1.10 is x¯=
50.573. If we let µdenote the mean of the breaking strengths of all possible trash bags of the
new type and assume that σ equals 1.61:
Calculate 95 percent confidence intervals for µ. (Round your answers to 3 decimal places.)
[50.068, 51.078]
Consider the trash bag problem. Suppose that an independent laboratory has tested trash
bags and has found that no 30-gallon bags that are currently on the market have a mean
breaking strength of 50 pounds or more. On the basis of these results, the producer of the
new, improved trash bag feels sure that its 30-gallon bag will be the strongest such bag on
the market if the new trash bag’s mean breaking strength can be shown to be at least 50
1
, Page 2 of 35
pounds. The mean of the sample of 39 trash bag breaking strengths in Table 1.10 is x¯=
50.573. If we let µ denote the mean of the breaking strengths of all possible trash bags of the
new type and assume that σ equals 1.61:
Using the 95 percent confidence interval, can we be 95 percent confident that µ is at least 50
pounds?
Yes, because 95% interval is above 50
Recall that a bank manager has developed a new system to reduce the time customers spend
waiting to be served by tellers during peak business hours. The mean waiting time during
peak business hours under the current system is roughly 9 to 10 minutes. The bank manager
hopes that the new system will have a mean waiting time that is less than six minutes. The
mean of the sample of 91 bank customer waiting times is x¯= 5.41. If we let µdenote the
mean of all possible bank customer waiting times using the new system and assume
that σ equals 2.42:
Calculate 99 percent confidence intervals for µ. (Round your answers to 3 decimal places.)
[4.757, 6.063]
Recall that a bank manager has developed a new system to reduce the time customers spend
waiting to be served by tellers during peak business hours. The mean waiting time during
peak business hours under the current system is roughly 9 to 10 minutes. The bank manager
hopes that the new system will have a mean waiting time that is less than six minutes. The
mean of the sample of 91 bank customer waiting times is x¯= 5.41. If we let µdenote the
2
, Page 3 of 35
mean of all possible bank customer waiting times using the new system and assume
that σ equals 2.42:
Using the 99 percent confidence interval, can the bank manager be 99 percent confident
that µ is less than six minutes? Explain.
No, the 99% interval extends above mean 6
The mean and the standard deviation of the sample of 100 bank customer waiting times are
x¯= 5.01 and s = 2.116.
Calculate a t-based 95 percent confidence interval for µ, the mean of all possible bank
customer waiting times using the new system. (Choose the nearest degree of freedom for the
given sample size. Round your answers to 3 decimal places.)
[4.590, 5.430]
The value of the test statistic is compared with a(n) ________ in order to decide whether the
null hypothesis can be rejected.
critical value
The area under the normal curve between z = 0 and z = 1 is ________ the area under the
normal curve between z = 1 and z = 2.
greater than
Which of the following is not continuous probability distributions?
binominal
3
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If [a,b] denotes an arbitrary interval of numbers on the real number line, Find the probability
when P(x = a)
0
Suppose that we will randomly select a sample of 64 measurements from a population having
a mean equal to 20 and a standard deviation equal to 4.
Describe the shape of the sampling distribution of the sample mean x.
normally distributed
Suppose that we will randomly select a sample of 64 measurements from a population having
a mean equal to 20 and a standard deviation equal to 4. Find the mean and the standard
deviation of the sampling distribution of the sample mean x . (Round your answer to 1
decimal place.)
mean = 20 standard deviation = .5
Suppose that we will randomly select a sample of 64 measurements from a population having
a mean equal to 20 and a standard deviation equal to 4. Calculate the probability that we will
obtain a sample mean greater than 21; that is, calculate P(x> 21). Hint: Find the z value
corresponding to 21 by using and because we wish to calculate a probability about x. (Use the
rounded standard error to compute the rounded Z-score used to find the probability. Round
your answer to 4 decimal places. Round z-scores to 2 decimal places.)
0
4
