Question: The 99% confidence interval for the mean IQ of all students at this university is (98.8, 108.8). Which of the following is the correct interpretation of this interval?
Answer Choices:
A. We have 99% confidence that µ is between 98.8 and 108.8.
B. We have 99% confidence that the mean IQ of all students at this university is between 98.8 and 108.8.
C. 99% of all students at this university have IQs between 98.8 and 108.8.
D. We have 99% confidence that the mean IQ of all students at this university is between 98.8 and 108.8.
Answer: B – We have 99% confidence that the mean IQ of all students at this university is between 98.8 and 108.8.
Question: Which of the following statements is true?
Answer Choices:
A. If possible, we want to make the probability of making a type I error as large as possible and make the probability of a type II error as small as possible.
B. If possible, we want to make the probability of making a type I error as small as possible and make the probability of a type II error as large as possible.
C. If possible, we want to make the probability of making a type I error as large as possible and make the probability of a type II error as large as possible.
D. If possible, we want to make the probability of making a type I error as small as possible and make the probability of a type II error as small as possible.
Answer: D – If possible, we want to make the probability of making a type I error as small as possible and make the probability of a type II error as small as possible.
Question: Atlantis Paradise Island is an ocean-themed resort on Paradise Island (PI) in the Bahamas (B). Of interest is to determine the proportion of all visitors to the Bahamas in 2019 that spent some time at Atlantis Paradise Island. Based on this information, what is the population of interest?
Answer Choices:
A. All visitors to the Bahamas in 2019.
B. The proportion of all visitors to the Bahamas in 2019 that spent some time at Atlantis Paradise Island.
C. Mean age of visitors to the Bahamas in 2019 that spent some time at Atlantis Paradise Island.
D. The proportion of all residents in the Bahamas that spent some time at Atlantis Paradise Island.
Answer: A – All visitors to the Bahamas in 2019.
Question: Atlantis Paradise Island is an ocean-themed resort on Paradise Island (PI) in the Bahamas (B). Of interest is to determine the proportion of all visitors to the Bahamas in 2019 that spent some time at Atlantis Paradise Island. Based on a sample of 400 visitors to the Bahamas in 2019, 120 visitors, or 30%, indicated that they spent some time at Atlantis Paradise Island. In this scenario, 30% is an example of a parameter or a statistic?
Answer Choices:
A. Statistic
B. Parameter
Answer: A – Statistic
Question: Atlantis Paradise Island is an ocean-themed resort on Paradise Island (PI) in the Bahamas (B). Of interest is to determine the proportion of all visitors to the Bahamas in 2019 that spent some time at Atlantis Paradise Island. Based on a brochure published by the resort, the proportion of tourists who visit the Bahamas and spent time at the Atlantis Paradise Island is 0.3. A statement about a population parameter, such as π = 0.3, is which of the following?
Answer Choices:
A. Parameter
B. Population
C. Statistic
D. Hypothesis
Answer: A – Parameter
Question: In partnership with the U.S. Department of Transportation, the Commonwealth of Virginia, the City of Richmond and Henrico County, GRTC and the Project Team launched the GRTC Pulse service on Sunday, June 24, 2018. What type of characteristic is the day GRTC Pulse service was launched?
Answer Choices:
A. Discrete quantitative variable
B. Categorical variable
C. Qualitative variable
D. Constant
Answer: D – Constant
Question: For all passengers who have ridden the GRTC Pulse since service was launched, of interest is to determine the mean age of all the passengers. What type of characteristic is mean age of all passengers who have ridden the GRTC Pulse?
Answer Choices:
A. Categorical variable
B. Discrete quantitative variable
C. Constant
D. Continuous quantitative variable
Answer: D – Continuous quantitative variable
Question: As they board, passengers are asked if they live in the City of Richmond, Henrico County, Chesterfield County, Hanover County, or another location (5 options). The location in which a GRTC Pulse passenger lives is what type of characteristic?
Answer Choices:
A. Constant
B. Discrete quantitative variable
C. Categorical variable
D. Continuous quantitative variable
Answer: C – Categorical variable
Question: Suppose that every day the proportion of all passengers on the GRTC Pulse that are either students or employees of VCU is determined. Based on this, the proportion of daily passengers on the GRTC Pulse who are either students or employees of VCU is what type of characteristic?
Answer Choices:
A. Continuous quantitative variable
B. Constant
C. Discrete quantitative variable
Answer: A – Continuous quantitative variable
Question: For all passengers who have ridden the GRTC Pulse since service was launched, of interest is to determine the mean age of all the passengers. Suppose a sample of 100 passengers who have ridden the GRTC Pulse since service was launched was selected. Passengers employed by other agencies and companies are excluded from the sample. In this scenario, what type of bias could this cause?
Answer Choices:
A. Nonresponse bias
B. Response bias
C. Selection bias
D. Confounding bias
Answer: C – Selection bias
Question: The population of interest is all VCU employees and the parameter of interest is proportion of all VCU employees who use the GRTC Pulse service. Suppose a sample of 100 VCU employees were randomly selected and contacted, but only 50 of them responded and answered the questions. If the characteristics of those who did respond and those who did not respond are different, what type of bias would this create?
Answer Choices:
A. Confounding bias
B. Response bias
C. Nonresponse bias
D. Selection bias
Answer: C – Nonresponse bias
Question: An Italian restaurant is interested in comparing a new method for preparing ravioli with the current method. They decide to conduct a study, as described below, to determine which method they will use. The study takes place over a two-week period and involves all customers who order ravioli during that time. With each order, a coin is flipped. If the coin lands on heads, the ravioli is prepared using the new method; if the coin lands on tails, the ravioli is prepared using the current method. After the meal, the customers are given a short, anonymous questionnaire in which they are asked to rate the quality of the ravioli on a scale of 1 to 10 (with larger numbers reflecting higher satisfaction). At the end of two weeks the data are analyzed and the results compared. As described, is this an example of a controlled experiment or an observational study?
Answer Choices:
A. Controlled experiment
B. Observational study
Answer: A – Controlled experiment
Question: An Italian restaurant is interested in comparing a new method for preparing ravioli with the current method. They decide to conduct a study, as described below, to determine which method they will use. The study takes place over a two-week period and involves all customers who order ravioli during that time. With each order, a coin is flipped. If the coin lands on heads, the ravioli is prepared using the new method; if the coin lands on tails, the ravioli is prepared using the current method. After the meal, the customers are given a short, anonymous questionnaire in which they are asked to rate the quality of the ravioli on a scale of 1 to 10 (with larger numbers reflecting higher satisfaction). At the end of two weeks the data are analyzed and the results compared. As described, is this an example of a controlled experiment or an observational study?
Answer Choices:
A. Controlled experiment
B. Observational study
Answer: A – Controlled experiment
Question: True or false: a stem-and-leaf plot and a histogram are graphical methods for displaying qualitative data.
Answer Choices:
A. True
B. False
Answer: B – False
Question: Which of the following statistics is a measure of spread that would be resistant to outliers?
Answer Choices:
A. Mean
B. Median
C. Range
D. Interquartile Range
E. Standard deviation
Answer: D – Interquartile Range
Question: When describing a distribution, which of the following things must you describe?
Answer Choices:
A. Center, only
B. Center, size, shape and unusual features
C. Center and spread
D. Center, spread, shape and unusual features
Answer: D – Center, spread, shape and unusual features