Math 221: Statistics
If a confidence interval is known to be (43.83, 46.37), what would be its margin of error? 3.54 0.64 2.54 1.27
1.27
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 324 158 197 157
158
In a sample of 10 CEOs, they spent an average of 12.5 hours each week looking into new product opportunities with a sample standard deviation of 4.9 hours. Find the 95% confidence interval. Assume the times are normally distributed. (7.6, 17.4) (9.5, 15.5) (9.4, 16.4) (9.0, 16.0)
(9.0, 16.0)
Which of the following is most likely to lead to a large margin of error? small mean large sample size small sample size small standard deviation
small sample size
Market research indicates that a new product has the potential to make the company an additional $1.6 million, with a standard deviation of $2.0 million. If these estimates were based on a sample of 8 customers from a normally distributed data set, what would be the 95% confidence interval? (0.00, 3.27) (0.21, 3.00) (-0.40, 3.60) (-0.07, 3.27)
(-0.07, 3.27)
What is the 97% confidence interval for a sample of 204 soda cans that have a mean amount of 12.05 ounces and a standard deviation of 0.08 ounces? (12.033, 12.067) (11.970, 12.130) (11.970, 12.130) (12.038, 12.062)
(12.038, 12.062)
In a sample of 28 cups of coffee at the local coffee shop, the temperatures were normally distributed with a mean of 182.5 degrees with a sample standard deviation of 14.1 degrees. What would be the 95% confidence interval for the temperature of your cup of coffee? (177.28, 187.72) (177.03, 187.97) (168.40, 196.60) (148.40, 176.60)
(177.03, 187.97)
Under a time crunch, you only have time to take a sample of 15 water bottles and measure their contents. The sample had a mean of 20.05 ounces with a sample standard deviation of 0.3 ounces. What would be the 90% confidence interval, when we assumed these measurements are normally distributed? (19.75, 20.35) (19.91, 20.19) (19.88, 20.22) (19.92, 20.18)
(19.91, 20.19)
Market research indicates that a new product has the potential to make the company an additional $3.8 million, with a standard deviation of $1.8 million. If this estimate was based on a sample of 10 customers, what would be the 90% confidence interval? (3.06, 4.54) (2.00, 5.60) (2.51, 5.09) (2.76, 4.84)
(2.76, 4.84)
In a sample of 8 high school students, they spent an average of 24.8 hours each week doing sports with a standard deviation of 3.2 hours. Find the 95% confidence interval. (24.10, 25.50) (22.66, 26.94) (21.60, 28.00) (22.12, 27.48)
(22.12, 27.48)
In a sample of 57 temperature readings taken from the freezer of a restaurant, the mean is 29.6 degrees and the population standard deviation is 2.7 degrees. What would be the 80% confidence interval for the temperatures in the freezer? (31.90, 32.44) (29.14, 30.06) (24.25, 35.05) (26.91, 32.31)
(29.14, 30.06)
In a sample of 19 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? (3.337, 4.103) (3.199, 4.241) (3.369, 4.071) (3.371, 4.069)
(3.369, 4.071)
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% confidence interval for the amount of time they spend online each week? (30.86, 32.74) (29.99, 33.61) (24.50, 39.10) (28.15, 35.45)
(30.86, 32.74)
In a random sample of fourteen people, the mean time at lunch was 35.6 minutes with a standard deviation of 8.2 minutes. Assuming the data are normally distributed, what would be the 85% confidence interval? (32.25, 38.95) (32.33, 38.87) (30.87, 40.33) (32.45, 38.75)
(32.25, 38.95)
In a sample of 15 stuffed animals, you find that they weigh an average of 8.56 ounces with a standard deviation of 0.07 ounces. Find the 92% confidence interval. (8.526, 8.594) (8.543, 8.577) (8.528, 8.591) (8.521, 8.599)
(8.526, 8.594)
What is the 99% confidence interval for a sample of 36 seat belts that have a mean length of 85.6 inches long and a population standard deviation of 2.5 inches? (80.6, 90.6) (83.1, 88.1) (84.4, 86.8) (84.5, 86.7)
(84.5, 86.7)
(CO 3) Fifty-seven percent of employees make judgments about their co-workers based on the cleanliness of their desk. You randomly select 8 employees and ask them if they judge co-workers based on this criterion. The random variable is the number of employees who judge their co-workers by cleanliness. Which outcomes of this binomial distribution would be considered unusual? 1, 2, 8 1, 2, 8 0, 1, 8 0, 1, 2, 8
0, 1, 8
Sixty-seven percent of adults have looked at their credit score in the past six months. If you select 31 customers, what is the probability that at least 25 of them have looked at their score in the past six months? 0.043 0.970 0.073 0.030
0.073
Thirty-eight percent of consumers prefer to purchase electronics online. You randomly select 16 consumers. Find the probability that the number who prefer to purchase electronics online is at most 3. 0.912 0.027 0.088 0.380
0.088
Sixty-four percent of those that use drive through services believe that the employees are at least somewhat rude. If you asked 87 people who use drive through services if they believe that the employees are at least somewhat rude, what is the probability that at most 50 say yes? 0.015 0.039 0.915 0.124
0.124
Fifty-four percent of US teens have heard of a fax machine. You randomly select 12 US teens. Find the probability that the number of these selected teens that have heard of a fax machine is exactly six (first answer listed below). Find the probability that the number is more than 8 (second answer listed below). 0.284, 0.160 0.284, 0.120 0.217, 0.280 0.217, 0.120
0.217, 0.120
In the morning, about 28% of adults know what they will have for dinner. If one morning, you ask 22 adults if they know what they will have for dinner, what is the probability that more than 6 will say yes? 0.423 0.188 0.390 0.610
0.423
If a confidence interval is given from 8.52 to 10.23 and the mean is known to be 9.375, what is the maximum error? 0.428 1.710 0.855 8.520
0.855
One out of every 92 tax returns that a tax auditor examines requires an audit. If 50 returns are selected at random, what is the probability that less than 5 will need an audit? 0.0002 0.9999 0.9998 0.0109
0.9998
Out of each 100 products, 93 are ready for purchase by customers. If you selected 20 products, what would be the expected (mean) number that would be ready for purchase by customers? 18 19 20 93
19
Determine the minimum sample size required when you want to be 98% confident that the sample mean is within two units of the population mean. Assume a standard deviation of 5.75 in a normally distributed population. 43 45 23 44
45
If a confidence interval is given from 45.82 up to 55.90 and the mean is known to be 50.86, what is the margin of error? 2.52 5.04 45.82 10.08
5.04
(CO 3) Among teenagers, 73% prefer watching shows over the internet, rather than through cable. If you asked 104 teenagers if they preferred watching shows over the internet, rather than through cable, how many would you expect to say yes? 73 104 75 76
76
Determine the minimum sample size required when you want to be 80% confident that the sample mean is within 1.3 units of the population mean. Assume a standard deviation of 9.24 in a normally distributed population. 83 194 195 84
83
From a random sample of 58 businesses, it is found that the mean time the owner spends on administrative issues each week is 21.69 with a population standard deviation of 3.23. What is the 95% confidence interval for the amount of time spent on administrative issues? A. (19.24, 24.14) B. (21.78, 22.60) C. (20.86, 22.52) D. (20.71, 22.67)
C. (20.86, 22.52)
A computer manufacturer estimates that its cheapest screens will last less than 2.8 years. A random sample of 61 of these screens has a mean life of 2.6 years. The population is normally distributed with a population standard deviation of 0.88 years. At α=0.02, what type of test is this and can you support the organization's claim using the test statistic? Claim is alternative, fail to reject the null and cannot support claim as test statistic (-1.78) is not in the rejection region defined by the critical value (-2.05) Claim is null, reject the null and cannot support claim as test statistic (-1.78) is not in the rejection region defined by the critical value (-2.05) Claim is alternative, reject the null and support claim as test statistic (-1.78) is not in the rejection region defined by the critical value (-2.05) Claim is null, fail to reject the null and cannot support claim as test statistic (-1.78) is not in the rejection region defined by the critical value (-2.05)
Claim is alternative, fail to reject the null and cannot support claim as test statistic (-1.78) is not in the rejection region defined by the critical value (-2.05)
A pharmaceutical company claims that the average cold lasts an average of 8.4 days. They are using this as a basis to test new medicines designed to shorten the length of colds. A random sample of 106 people with colds, finds that on average their colds last 8.5 days. The population is normally distributed with a population standard deviation of 0.9 days. At α=0.02, what type of test is this and can you support the company's claim using the p-value? Claim is alternative, fail to reject the null and support claim as the p-value (0.126) is less than alpha (0.02) Claim is alternative, reject the null and support claim as the p-value (0.126) is greater than alpha (0.02) Claim is null, fail to reject the null and support claim as the p-value (0.253) is greater than alpha (0.02) Claim is null, reject the null and cannot support claim as the p-value (0.253) is less than alpha (0.02)
Claim is null, fail to reject the null and support claim as the p-value (0.253) is greater than alpha (0.02)
A consumer research organization states that the mean caffeine content per 12-ounce bottle of a population of caffeinated soft drinks is 37.8 milligrams. You find a random sample of 48 12-ounce bottles of caffeinated soft drinks that has a mean caffeine content of 41.5 milligrams. Assume the population standard deviation is 12.5 milligrams. At α=0.05, what type of test is this and can you reject the organization's claim using the test statistic? Claim is alternative, fail to reject the null and support claim as test statistic (2.05) is not in the rejection region defined by the critical value (1.64) Claim is null, reject the null and reject claim as test statistic (2.05) is in the rejection region defined by the critical value (1.96) Claim is null, fail to reject the null and reject claim as test statistic (2.05) is not in the rejection region defined by the critical value (1.96) Claim is alternative, reject the null and support claim as test statistic (2.05) is in the rejection region defined by the critical value (1.64)
Claim is null, reject the null and reject claim as test statistic (2.05) is in the rejection region defined by the critical value (1.96)
Seventy-nine percent of products come off the line ready to ship to distributors. Your quality control department selects 12 products randomly from the line each hour. Looking at the binomial distribution, if fewer than how many are within specifications would require that the production line be shut down (unusual) and repaired? Fewer than 7 Fewer than 6 Fewer than 9 Fewer than 10
Fewer than 7
A transportation organization claims that the mean travel time between two destinations is about 12 minutes. Write the null and alternative hypotheses and note which is the claim. Ho: μ = 12 (claim), Ha: μ ≠ 12 Ho: μ > 12, Ha: μ ≤ 12 (claim) Ho: μ = 12 (claim), Ha: μ ≤ 12 Ho: μ ≠ 12, Ha: μ = 12 (claim)
Ho: μ = 12 (claim), Ha: μ ≠ 12
A consumer analyst reports that the mean life of a certain type of alkaline battery is no more than 63 months. Write the null and alternative hypotheses and note which is the claim. Ho: μ ≤ 63, Ha: μ > 63 (claim) μ > 63 (claim), Ha: μ ≤ 63 Ho: μ = 63 (claim), Ha: μ ≥ 63 Ho: μ ≤ 63 (claim), Ha: μ > 63
Ho: μ ≤ 63 (claim), Ha: μ > 63
A business claims that the mean time that customers wait for service is at most 9.2 minutes. Write the null and alternative hypotheses and note which is the claim. Ho: μ > 9.2 (claim), Ha: μ > 9.2 Ho: μ ≥ 9.2, Ha: μ ≤ 9.2 (claim) Ho: μ ≤ 9.2 (claim), Ha: μ > 9.2 Ho: μ > 9.2, Ha: μ ≤ 9.2 (claim)
Ho: μ ≤ 9.2 (claim), Ha: μ > 9.2
In a situation where the sample size was decreased from 39 to 29, what would be the impact on the confidence interval? It would become wider due to using the t distribution It would become narrower due to using the z distribution It would become narrower with fewer values It would remain the same as sample size does not impact confidence intervals
It would become wider due to using the t distribution
In a situation where the sample size was 28 while the population standard deviation was increased, what would be the impact on the confidence interval? It would become narrower due to using the t distribution It would become wider with more dispersion in values It would widen with more values It would become wider due to using the z distribution
It would become wider with more dispersion in values
The 95% confidence interval for these parts is 56.98 to 57.05 under normal operations. A systematic sample is taken from the manufacturing line to determine if the production process is still within acceptable levels. The mean of the sample is 56.99. What should be done about the production line? Keep the line operating as it is inside the confidence interval Stop the line as it is inside the confidence interval Stop the line as it is outside the confidence interval Keep the line operating as it is outside the confidence interval
Keep the line operating as it is inside the confidence interval
On the production line the company finds that 95.6% of products are made correctly. You are responsible for quality control and take batches of 30 products from the line and test them. What number of the 30 being incorrectly made would cause you to shut down production? More than 25 Less than 28 Less than 27 Less than 26
Less than 27
You needed a supplier that could provide parts as close to 76.8 inches in length as possible. You receive four contracts, each with a promised level of accuracy in the parts supplied. Which of these four would you be most likely to accept? Mean of 76.8 with a 99% confidence interval of 76.6 to 77.0 Mean of 76.800 with a 99% confidence interval of 76.5 to 77.1 Mean of 76.8 with a 95% confidence interval of 76.6 to 77.0 Mean of 76.800 with a 90% confidence interval of 76.6 to 77.0
Mean of 76.8 with a 99% confidence interval of 76.6 to 77.0
A researcher wants to determine if zinc levels are different between the top of a glass of water and the bottom of a glass of water. Many samples of water are taken. From half, the zinc level at the top is measured and from half, the zinc level at the bottom is measured. Would this be a valid matched pair test? Yes, as long as they are all from the same faucet Yes, as long as there are an equal number of glasses in each group No, as the measurements of top and bottom should be from the same glass No, as the zinc levels cannot be accurately measured
No, as the measurements of top and bottom should be from the same glass
A credit reporting agency claims that the mean credit card debt in a town is greater than $3500. A random sample of the credit card debt of 20 residents in that town has a mean credit card debt of $3600 and a standard deviation of $391. At α=0.10, can the credit agency's claim be supported, assuming this is a normally distributed data set? No, since p-value of 0.13 is greater than 0.10, reject the null. Claim is null, so is not supported Yes, since p-value of 0.13 is greater than 0.10, fail to reject the null. Claim is null, so is supported No, since p of 0.13 is greater than 0.10, fail to reject the null. Claim is alternative, so is not supported Yes, since p-value of 0.13 is less than 0.55, reject the null. Claim is alternative, so is supported
No, since p of 0.13 is greater than 0.10, fail to reject the null. Claim is alternative, so is not supported
A business receives supplies of copper tubing where the supplier has said that the average length is 26.70 inches so that they will fit into the business' machines. A random sample of 48 copper tubes finds they have an average length of 26.75 inches. The population standard deviation is assumed to be 0.20 inches. At α=0.05, should the business reject the supplier's claim? Yes, since p<α, we reject the null and the null is the claim Yes, since p>α, we fail to reject the null and the null is the claim No, since p>α, we reject the null and the null is the claim No, since p>α, we fail to reject the null and the null is the claim
No, since p>α, we fail to reject the null and the null is the claim
If two samples A and B had the same mean and standard deviation, but sample A had a larger sample size, which sample would have the wider 95% confidence interval? Sample B as its sample is more dispersed Sample B as it has the smaller sample Sample A as it comes first Sample A as it has the larger sample
Sample B as it has the smaller sample
Supplier claims that they are 95% confident that their products will be in the interval of 20.45 to 21.05. You take samples and find that the 95% confidence interval of what they are sending is 20.32 to 21.48. What conclusion can be made? The supplier is more accurate than they claimed The supplier products have a lower mean than claimed The supplier is less accurate than they have claimed The supplier products have a higher mean than claimed
The supplier is less accurate than they have claimed
Say that a supplier claims they are 99% confident that their products will be in the interval of 50.02 to 50.38. You take samples and find that the 99% confidence interval of what they are sending is 50.03 to 50.37. What conclusion can be made? The supplier products have a lower mean than claimed The supplier is less accurate than they claimed The supplier is more accurate than they claimed The supplier products have a higher mean than claimed
The supplier is more accurate than they claimed
A scientist claims that the mean gestation period for a fox is less than 50.3 weeks. If a hypothesis test is performed that rejects the null hypothesis, how would this decision be interpreted? There is enough evidence to support the scientist's claim that the gestation period is less than 50.3 weeks There is not enough evidence to support the scientist's claim that the gestation period is more than 50.3 weeks There is not enough evidence to support the scientist's claim that the gestation period is 50.3 weeks The evidence indicates that the gestation period is more than 50.3 weeks
There is enough evidence to support the scientist's claim that the gestation period is less than 50.3 weeks
A marketing organization claims that none of its employees are paid minimum wage. If a hypothesis test is performed that fails to reject the null hypothesis, how would this decision be interpreted? There is sufficient evidence to support the claim that some of the employees are paid minimum wage There is not sufficient evidence to support the claim that none of the employees are paid minimum wage There is not sufficient evidence to support the claim that some of the employees are paid minimum wage There is sufficient evidence to support the claim that none of the employees are paid minimum wage
There is sufficient evidence to support the claim that none of the employees are paid minimum wage
Why might a company use a lower confidence interval, such as 80%, rather than a high confidence interval, such as 99%? They are in the medical field, so cannot be so precise They make computer parts where they are too small for higher accuracy They track the migration of fish where accuracy is not as important They make children's toys where imprecision is expected
They track the migration of fish where accuracy is not as important
Ten rugby balls are randomly selected from the production line to see if their shape is correct. Over time, the company has found that 89.4% of all their rugby balls have the correct shape. If exactly 6 of the 10 have the right shape, should the company stop the production line? No, as the probability of six having the correct shape is not unusual Yes, as the probability of six having the correct shape is not unusual Yes, as the probability of six having the correct shape is unusual No, as the probability of six having the correct shape is unusua
Yes, as the probability of six having the correct shape is unusual
The company's cleaning service states that they spend more than 46 minutes each time the cleaning service is there. The company times the length of 37 randomly selected cleaning visits and finds the average is 47.6 minutes. Assuming a population standard deviation of 5.2 minutes, can the company support the cleaning service's claim at α=0.10? No, since p>α, we fail to reject the null. The claim is the alternative, so the claim is not supported Yes, since p<α, we reject the null. The claim is the alternative, so the claim is supported No, since p<α, we reject the null. The claim is the alternative, so the claim is not supported Yes, since p>α, we fail to reject the null. The claim is the null, so the claim is supported
Yes, since p<α, we reject the null. The claim is the alternative, so the claim is supported
A customer service phone line claims that the wait times before a call is answered by a service representative is less than 3.3 minutes. In a random sample of 62 calls, the average wait time before a representative answers is 3.24 minutes. The population standard deviation is assumed to be 0.29 minutes. Can the claim be supported at α=0.08? Yes, since test statistic is not in the rejection region defined by the critical value, reject the null. The claim is the alternative, so the claim is supported No, since test statistic is in the rejection region defined by the critical value, fail to reject the null. The claim is the alternative, so the claim is not supported No, since test statistic is in the rejection region defined by the critical value, reject the null. The claim is the alternative, so the claim is not supported Yes, since test statistic is in the rejection region defined by the critical value, reject the null. The claim is the alternative, so the claim is supported
Yes, since test statistic is in the rejection region defined by the critical value, reject the null. The claim is the alternative, so the claim is supported
A university claims that the mean time professors are in their offices for students is at least 6.5 hours each week. A random sample of eight professors finds that the mean time in their offices is 6.2 hours each week. With a sample standard deviation of 0.49 hours from a normally distributed data set, can the university's claim be supported at α=0.05? No, since the test statistic is in the rejection region defined by the critical value, the null is rejected. The claim is the null, so is not supported Yes, since the test statistic is not in the rejection region defined by the critical value, the null is not rejected. The claim is the null, so is supported Yes, since the test statistic is in the rejection region defined by the critical value, the null is not rejected. The claim is the null, so is supported No, since the test statistic is not in the rejection region defined by the critical value, the null is rejected. The claim is the null, so is not supported
Yes, since the test statistic is not in the rejection region defined by the critical value, the null is not rejected. The claim is the null, so is supported
A car company claims that its cars achieve an average gas mileage of at least 26 miles per gallon. A random sample of eight cars form this company have an average gas mileage of 25.5 miles per gallon and a standard deviation of 1 mile per gallon. At α=0.06, can the company's claim be supported, assuming this is a normally distributed data set? Yes, since the test statistic of -1.41 is not in the rejection region defined by the critical value of -1.55, the null is rejected. The claim is the null, so is supported No, since the test statistic of -1.41 is in the rejection region defined by the the critical value of -1.77, the null is rejected. The claim is the null, so is not supported Yes, since the test statistic of -1.41 is not in the rejection region defined by the critical value of -1.77, the null is not rejected. The claim is the null, so is supported No, since the test statistic of -1.41 is close to the critical value of -1.24, the null is not rejected. The claim is the null, so is supported
Yes, since the test statistic of -1.41 is not in the rejection region defined by the critical value of -1.77, the null is not rejected. The claim is the null, so is supported
A company making refrigerators strives for the internal temperature to have a mean of 37.5 degrees with a standard deviation of 0.6 degrees, based on samples of 100. A sample of 100 refrigerators have an average temperature of 37.53 degrees. Are the refrigerators within the 90% confidence interval? No, the temperature is outside the confidence interval of (37.40, 37.60) Yes, the temperature is within the confidence interval of (37.40, 37.60) No, the temperature is outside the confidence interval of (36.90, 38.10) Yes, the temperature is within the confidence interval of (36.90, 38.10)
Yes, the temperature is within the confidence interval of (37.40, 37.60)
If you were designing a study that would benefit from data points with high values, you would want the input variable to have: a large sample size a large mean a large standard deviation a large margin of error
a large mean
If the null hypothesis is not rejected when it is false, this is called __________. a type I error the Empirical Rule an alternative hypothesis a type II error
a type II error
A bottle of water is supposed to have 12 ounces. The bottling company has determined that 98% of bottles have the correct amount. Which of the following describes a binomial experiment that would determine the probability that a case of 36 bottles has all bottles properly filled? n=36, p=0.98, x=36 n=0, p=0.98, x=36 n=12, p=36, x=98 n=36, p=0.98, x=12
n=36, p=0.98, x=36
If a computer manufacturer needed a supplier that could produce parts that were very precise, what characteristics would be better? narrow confidence interval at low confidence level narrow confidence interval at high confidence level wide confidence interval with high confidence level wide confidence interval with low confidence level
narrow confidence interval at high confidence level
In a sample of 18 kids, their mean time on the internet on the phone was 28.6 hours with a sample standard deviation of 5.6 hours. Which distribution would be most appropriate to use, when we assume these times are normally distributed? z distribution as the sample standard deviation always represents the population t distribution as the sample standard deviation is unknown t distribution as the population standard deviation is unknown while the times are assumed to be normally distributed z distribution as the population standard deviation is known while the times are assumed to be normally distributed
t distribution as the population standard deviation is unknown while the times are assumed to be normally distributed
In a hypothesis test, the claim is μ≤40 while the sample of 27 has a mean of 41 and a sample standard deviation of 5.9 from a normally distributed data set. In this hypothesis test, would a z test statistic be used or a t test statistic and why? z test statistic would be used as the mean is greater than 30 t test statistic would be used as the data are normally distributed with an unknown population standard deviation z test statistic would be used as the population standard deviation is known t test statistic would be used as the standard deviation is less than 10
t test statistic would be used as the data are normally distributed with an unknown population standard deviation
Which of the following are most likely to lead to a wide confidence interval? small standard deviation small sample size large mean large sample size
small sample size
From a random sample of 55 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? (4.84, 4.96) (4.82, 4.98) (4.83, 4.97) (4.81, 4.99)
(4.81, 4.99)
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? (50.64, 53.36) (51.33, 52.67) (51.34, 52.66) (50.45, 53.55)
(50.45, 53.55)
Determine the minimum sample size required when you want to be 95% confident that the sample mean is within two units of the population mean. Assume a population standard deviation of 4.3 in a normally distributed population. 20 22 16 18
18
Determine the minimum sample size required when you want to be 99% confident that the sample mean is within 0.50 units of the population mean. Assume a population standard deviation of 2.9 in a normally distributed population. 130 224 223 129
224
The probability of someone ordering the daily special is 71%. If the restaurant expected 65 people for lunch, how many would you expect to order the daily special? 46 51 35 34
46
An amusement park claims that the average daily attendance is at least 15,000. Write the null and alternative hypotheses and note which is the claim. Ho: μ > 15000 (claim), Ha: μ = 15000 >Ho: μ ≥ 15000 (claim), Ha: μ < 15000 Ho: μ ≤ 15000, Ha: μ > 15000 (claim) Ho: μ = 15000, Ha: μ ≤ 15000 (claim)
>Ho: μ ≥ 15000 (claim), Ha: μ < 15000
A sprinkler manufacturer claims that the average activating temperatures is at least 134 degrees. To test this claim, you randomly select a sample of 32 systems and find the mean activation temperature to be 133 degrees. Assume the population standard deviation is 3.3 degrees. Find the standardized test statistic and the corresponding p-value. z-test statistic = -1.71, p-value = 0.0432 z-test statistic = -1.71, p-value = 0.0865 z-test statistic = 1.71, p-value = 0.0432 z-test statistic = 1.71, p-value = 0.0865
z-test statistic = -1.71, p-value = 0.0432
A consumer group claims that the mean acceleration time from 0 to 60 miles per hour for a sedan is 8.4 seconds. A random sample of 33 sedans has a mean acceleration time from 0 to 60 miles per hour of 7.6 seconds. Assume the population standard deviation is 2.3 seconds. Find the standardized test statistic and the corresponding p-value. z-test statistic = -1.998, p-value = 0.023 z-test statistic = -1.998, p-value = 0.046 z-test statistic = 1.998, p-value = 0.046 z-test statistic = 1.998, p-value = 0.023
z-test statistic = -1.998, p-value = 0.046
