1. Which of the following experiments does not generate a continuous random variable? recording the number of miles traveled between two locations recording the number of minutes a customer waits on hold for technical support measuring the number

1.      Which of the following experiments does not generate a continuous random variable?

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recording the number of miles traveled between two locations

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recording the number of minutes a customer waits on hold for technical support

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measuring the number of ounces of soda in a bottle

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counting the number of customers who enter a store during the business day

3.125 points  

Question 2

1.      The exponential probability distribution is a discrete distribution that is often used to describe time between customer arrivals.

[removed] True

[removed] False

3.125 points  

Question 3

1.      According to the MIT Airline Data Project, American Airlines controlled 15.5% of the domestic market in 2010. A random sample of 125 domestic passengers that year was selected. Using the normal approximation to the binomial distribution, what is the probability that 20, 21, 22, 23, 24, or 25 passengers from this sample were on American Airline flights?

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0.5319

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0.6810

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0.2534

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0.4225

3.125 points  

Question 4

1.      Suppose the round-trip airfare between Philadelphia and Los Angeles a month before the departure date follows the normal probability distribution with a mean of $387.20 and a standard deviation of $68.50. What is the probability that a randomly selected airfare between these two cities will be between $325 and $425?

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0.2650

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0.1548

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0.3875

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0.5274

3.125 points  

Question 5

1.      Bob's golf score at his local course follows the normal distribution with a mean of 92.1 and a standard deviation of 3.8. The interval around the mean that contains 68% of Bob's golf scores is ________.

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84.5, 99.7

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80.7, 103.5

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90.2, 94.0

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88.3, 95.9

3.125 points  

Question 6

1.      Bananas are sold in bunches at a grocery store and typically consist of 4-8 bananas per bunch. Suppose the weight of these bunches follows a normal distribution with a mean of 3.54 pounds and a standard deviation of 0.63 pounds. What is the probability that a randomly selected bunch of bananas will weigh more than 3.0 pounds?

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0.9463

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0.5398

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0.6950

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0.8051

3.125 points  

Question 7

1.      According to Bureau of Labor Statistics, 22.1% of the total part-time workforce in the U.S. was between the ages of 25 and 34 during the 3rd quarter of 2011. A random sample of 80 part-time employees was selected during this quarter. Using the normal approximation to the binomial distribution, what is the probability that exactly 21 people from this sample were between the ages of 25 and 34?

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0.2294

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0.0319

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0.1515

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0.0721

3.125 points  

Question 8

1.      If the population does not follow the normal probability distribution, the Central Limit Theorem tells us that the sample means will be normally distributed with sufficiently large sample size. In most cases, sample sizes of 5 or more will result in sample means being normally distributed, regardless of the shape of the population distribution.

[removed] True

[removed] False

3.125 points  

Question 9

1.      Deanna has been hired to visit the local shopping mall to conduct a survey about the upcoming political election. She needs to select respondents at the mall and ask them questions about their voting tendencies. Deanna decides to position herself by the only entrance to the mall and select every 10th shopper entering the mall to participate. Which of the following sampling techniques best describes Deanna's method?

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simple random

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cluster

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probability

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systematic

3.125 points  

Question 10

1.      A ________ sample is a sample in which every member of the population has an equal chance of being chosen.

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probability

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stratified

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systematic

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simple random

3.125 points  

Question 11

1.      Suppose the average amount spent per shopper at the Super Fresh Grocery Store last month was $46.10. A sample of 25 transactions from last month was randomly selected. Another random sample of 50 transactions was also collected. We can be certain that the sampling error from the sample of 50 customers will be less than the sampling error from the 25 customers.

[removed] True

[removed] False

3.125 points  

Question 12

1.      A common source of nonsampling errors is a survey that contains ambiguous questions in the eyes of the respondent.

[removed] True

[removed] False

3.125 points  

Question 13

1.      An Epson inkjet printer ad advertises that the black ink cartridge will provide enough ink for an average of 245 pages. Assume that this claim is accurate and that the standard deviation for this population is 15 pages. A random sample of 33 customers was surveyed about the number of pages they were able to print with their black ink cartridges. What the probability that the sample mean will be 246 pages or less?

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0.6480

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0.1093

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0.3520

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0.8729

3.125 points  

Question 14

1.      The presence of sampling error is an indication that an improper sampling technique was used.

[removed] True

[removed] False

3.125 points  

Question 15

1.      A random sample of 30 business students required an average of 43.4 minutes to complete a statistics exam. Assume that the population standard deviation to complete the exam was 8.7 minutes. The 95% confidence interval around this sample mean is ________.

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(40.3, 46.5)

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(41.4, 45.4)

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(42.0, 44.8)

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(40.8, 46.0)

3.125 points  

Question 16

1.      A random sample of 30 business students required an average of 43.4 minutes to complete a statistics exam. Assume that the population standard deviation to complete the exam was 8.7 minutes. The 99% confidence interval around this sample mean is ________.

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(37.1, 49.8)

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(36.3, 50.5)

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(40.5, 46.3)

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(39.3, 47.5)

3.125 points  

Question 17

1.      John Charleston owns a heating oil delivery company that services 1,540 residences. John would like to estimate the number of customers that have oil storage tanks that are less than 100 gallons in capacity. A random sample of 200 customers found that 48 had an oil tank that was less than 100 gallons. The 99% confidence interval to estimate the proportion of customers with oil tanks less than 100 gallons is ________.

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(0.225, 0.255)

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(0.212, 0.268)

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(0.167, 0.313)

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(0.184, 0.296)

3.125 points  

Question 18

1.      A random sample of 30 business students required an average of 43.4 minutes to complete a statistics exam. Assume that the population standard deviation to complete the exam was 8.7 minutes. The margin of error for a 98% confidence interval around this sample mean is ________.

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3.70

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2.62

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3.12

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2.04

3.125 points  

Question 19

1.      The average natural gas bill for a random sample of 26 homes in the 19808 zip code during the month of March was $305.30 with a sample standard deviation of $46.50. The margin of error for a 98% confidence interval around this sample mean is ________.

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$25.20

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$20.15

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$18.69

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$22.66

3.125 points  

Question 20

1.      Verizon Wireless would like to estimate the proportion of households that use cell phones for their phone service without a land line. A random sample of 150 households was selected and 48 relied strictly on cell phones for their service. Using this sample, the point estimate for the proportion of households without land lines is ________.

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0.48

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0.53

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0.32

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0.25

3.125 points  

Question 21

1.      The average natural gas bill for a random sample of 26 homes in the 19808 zip code during the month of March was $305.30 with a sample standard deviation of $46.50. The critical value for a 95% confidence interval around this sample mean is ________.

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1.708

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1.706

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2.056

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2.060

3.125 points  

Question 22

1.      The National Center for Education Statistics would like to test the hypothesis that the proportion of Bachelor's degrees that were earned by women equals 0.60. A random sample of 140 college graduates with Bachelor degrees found that 75 were women. The National Center for Education Statistics would like to set α = 0.10. The p-value for this hypothesis test would be ________.

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0.0380

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0.0174

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0.1212

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0.1008

3.125 points  

Question 23

1.      The National Center for Education Statistics would like to test the hypothesis that the proportion of Bachelor's degrees that were earned by women equals 0.60. A random sample of 140 college graduates with Bachelor degrees found that 75 were women. The National Center for Education Statistics would like to set α = 0.10. Which one of the following statements is true?

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Because the p-value is less than α, we reject the null hypothesis and conclude that the proportion of Bachelor's degrees that were earned by women does not equal 0.60.

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Because the p-value is less than α, we fail to reject the null hypothesis and cannot conclude that the proportion of Bachelor's degrees that were earned by women does not equal 0.60.

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Because the p-value is greater than α, we fail to reject the null hypothesis and conclude that the proportion of Bachelor's degrees that were earned by women equals 0.60.

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Because the p-value is greater than α, we fail to reject the null hypothesis and cannot conclude that the proportion of Bachelor's degrees that were earned by women does not equal 0.60.

3.125 points  

Question 24

1.      A professor would like to test the hypothesis that the average number of minutes that a student needs to complete a statistics exam is equal to 45 minutes. A Type I error would occur if the professor concludes that the average exam time is

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equal to 45 minutes when, in reality, the average time is less than 45 minutes.

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equal to 45 minutes when, in reality, the average time is not equal to 45 minutes.

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not equal to 45 minutes when, in reality, the average time is equal to 45 minutes.

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not equal to 45 minutes when, in reality, the average time is greater than 45 minutes.

3.125 points  

Question 25

1.      Expedia would like to test the hypothesis that the proportion of United Airline flights that arrive on-time is less than 0.80. A random sample of 110 United Airline flights found that 82 arrived on-time. Expedia would like to set α = 0.02. Which one of the following statements is true?

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Because the p-value is greater than α, we fail to reject the null hypothesis and cannot conclude that the proportion of United Airline flights that arrive on-time is less than 0.80.

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Because the p-value is less than α, we reject the null hypothesis and conclude that the proportion of United Airline flights that arrive on-time is less than 0.80.

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Because the p-value is greater than α, we reject the null hypothesis and cannot conclude that the proportion of United Airline flights that arrive on-time is less than 0.80.

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Because the p-value is less than α, we fail to reject the null hypothesis and cannot conclude that the proportion of United Airline flights that arrive on-time is less than 0.80.

3.125 points  

Question 26

1.      A golfer claims that his average golf score at the course he plays regularly is less than 90. A random sample of 35 rounds of golf was selected and the scores were recorded. Assume that the standard deviation for the population of scores for this golfer is 3.4 and the true population mean for scores for this golfer is 88.2. Using α = 0.05, beta equals ________.

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0.0694

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0.1895

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0.0944

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0.1292

3.125 points  

Question 27

1.      Expedia would like to test the hypothesis that the proportion of United Airline flights that arrive on-time is less than 0.80. A random sample of 110 United Airline flights found that 82 arrived on-time. Expedia would like to set α = 0.02. The critical proportion for this hypothesis test would be ________.

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0.806

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0.722

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0.776

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0.795

3.125 points  

Question 28

1.      The pH scale measures the amount of alkalinity or acidity in a liquid and ranges from 0 to 14. The ideal pH for a swimming pool is 7.2. A pH that is too high or low can cause discomfort for the swimmers, especially in the eyes.
Chemicals need to be added to the water to adjust the pH to the desired level. Fifteen pH readings were taken at the Wilson Community Pool from different locations at 10 AM this morning. The average pH reading from this sample was 7.02 with a sample standard deviation of 0.40. Using   = 0.05 and the critical value approach, determine if corrective action is needed at this pool to adjust the pH value.Identify the null and alternative hypothesis

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H0:      7.2;    H1:    7.2

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H0:      7.2;    H1:  <7.2

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H0:      7.2;    H1:    7.2

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H0:    =7.2;    H1:    7.2

3.125 points  

Question 29

1.      The pH scale measures the amount of alkalinity or acidity in a liquid and ranges from 0 to 14. The ideal pH for a swimming pool is 7.2. A pH that is too high or low can cause discomfort for the swimmers, especially in the eyes.
Chemicals need to be added to the water to adjust the pH to the desired level. Fifteen pH readings were taken at the Wilson Community Pool from different locations at 10 AM this morning. The average pH reading from this sample
was 7.02 with a sample standard deviation of 0.40. Using   = 0.05 and the critical value approach, determine if corrective action is needed at this pool to adjust the pH value. Set a value and determine the significance level.

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0.95

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0.01

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0.05

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0.90

3.125 points  

Question 30

1.      The pH scale measures the amount of alkalinity or acidity in a liquid and ranges from 0 to 14. The ideal pH for a swimming pool is 7.2. A pH that is too high or low can cause discomfort for the swimmers, especially in the eyes.
Chemicals need to be added to the water to adjust the pH to the desired level. Fifteen pH readings were taken at the Wilson Community Pool from different locations at 10 AM this morning. The average pH reading from this sample was 7.02 with a sample standard deviation of 0.40. Using   = 0.05 and the critical value approach, determine if corrective action is needed at this pool to adjust the pH value.Determine the appropriate critical value.

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 3.145

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 2.145

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 1.96

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 2.0

3.125 points  

Question 31

1.      The pH scale measures the amount of alkalinity or acidity in a liquid and ranges from 0 to 14. The ideal pH for a swimming pool is 7.2. A pH that is too high or low can cause discomfort for the swimmers, especially in the eyes.
Chemicals need to be added to the water to adjust the pH to the desired level. Fifteen pH readings were taken at the Wilson Community Pool from different locations at 10 AM this morning. The average pH reading from this sample
was 7.02 with a sample standard deviation of 0.40. Using   = 0.05 and the critical value approach, determine if corrective action is needed at this pool to adjust the pH value. Calculate the appropriate test statistic.

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1.74

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-0.45

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-1.74

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0.45

3.125 points  

Question 32

1.      The pH scale measures the amount of alkalinity or acidity in a liquid and ranges from 0 to 14. The ideal pH for a swimming pool is 7.2. A pH that is too high or low can cause discomfort for the swimmers, especially in the eyes.
Chemicals need to be added to the water to adjust the pH to the desired level. Fifteen pH readings were taken at the Wilson Community Pool from different locations at 10 AM this morning. The average pH reading from this sample 
was 7.02 with a sample standard deviation of 0.40. Using   = 0.05 and the critical value approach, determine if correctiveaction is needed at this pool to adjust the pH value. State your conclusion.

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Because calculated t statistic is greater than t critical value, we reject the null hypothesis.
Therefore, Wilson Community Pool cannot conclude that the pH value is not equal to 7.2. Based on this
sample, corrective action needs to be taken.

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Because calculated t statistic is less than critical t value, we reject the null hypothesis.
Therefore, Wilson Community Pool cannot conclude that the pH value is not equal to 7.2. Based on this
sample, corrective action needs to be taken.

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Because the t calculated is greater than the critical t, we fail to reject the null hypothesis. Therefore, Wilson Community Pool conclude that the pH value is equal to 7.2. Based on this sample, no corrective action is needed.

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Because the t calculated is less than the critical t, we fail to reject the null hypothesis. Therefore, Wilson Community Pool conclude that the pH value is equal to 7.2. Based on this sample, no corrective action is needed.

 

               

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