All Questions And Answers For MATH 1281 Statistic Inference - Complete Solutions [A+ GUIDE]

An automobile producing company operates car dealerships that sell its cars. In order to assess the service costumers get at the dealerships a team from the Customer Relationship Department was assembled. The team was ...

An automobile producing company operates car dealerships that sell its cars. In order to assess the service costumers get at the dealerships a team from the Customer Relationship Department was assembled. The team was sent to 20 randomly selected dealerships. Each dealership was visited once by the team for an entire working day. During a visit the team interviewed all the customers that arrived at that dealership. One of the questions that each of the customers were asked is: "Do you currently possess a car made by our company?" The answers were marked down as "Yes", "No", or "Refuse to Answer", depending on the customer's response. Select the correct answer in each of the following 4 questions: Question 1 Correct Mark 1.00 out of 1.00 Flag question Question text The population in this survey is: Select one: a. The researchers that conducted the survey. b. Customers that arrive at dealerships of the company. c. The automobile producing company. d. Owners of cars that are produced by the company. Feedback The target of the survey is to assess the service that costumers get at the dealerships. The correct answer is: Customers that arrive at dealerships of the company. Question 2 Correct Mark 1.00 out of 1.00 Flag question Question text The sample in this survey is: Select one: a. The team that conducted the survey. b. Customers that arrive at dealerships of the company. c. "Yes", "No", or "Refuse to Answer". d. Customers that arrive at the selected dealerships during the day of visit. Feedback All the costumers that arrive at dealerships are the population. The subset of those that arrive to the 20 dealerships that were selected are the sample. The correct answer is: Customers that arrive at the selected dealerships during the day of visit. Question 3 Correct Mark 1.00 out of 1.00 Flag question Question text A parameter that may be targeted by this survey is: Select one: a. The percentage of costumers that possess a car made by the company. b. Customers that arrive at the selected dealerships during the day of visit. c. "Yes", "No", or "Refuse to Answer". d. Owners of cars that are produced by the company. Feedback "The percentage of costumers that possess a car made by the company" is the only answer that describes a characteristic of the population. The last answer describes a subset of the population, not a characteristic: The percentage of the subset within the entire population is a parameter, the subset itself is not. The correct answer is: The percentage of costumers that possess a car made by the company. Question 4 Correct Mark 1.00 out of 1.00 Flag question Question text A statistic that may be used to summarize the outcome of the survey is: Select one: a. "Yes". b. The percentage, among costumers that were interviewed, of those that do not possess a car made by the company c. Customers that arrive at the selected dealerships during the day of visit. d. The team that conducted the survey. Feedback "The percentage, among costumers that were interviewed, of those that do not possess a car made by the company" is the only answer that describes a characteristic of the sample. The third answer describes the sample, not a characteristic of it: The percentage of the subset within the sample is a statistic, the sample itself is not. The correct answer is: The percentage, among costumers that were interviewed, of those that do not possess a car made by the company Information Flag question Information text The Customers Service Center of a large bank receive calls from customers. The number of incoming calls between 8:00 AM and 8:10 AM in consecutive days were recorded. The number of incoming calls during the working days of the month of September were: 8, 10, 6, 7, 12, 7, 8, 7, 8, 6, 9, 4, 6, 14, 10, 10, 10, 10, 6, 10, 12, 7 The number of incoming calls during the working days of the month of February were: 9, 11, 14, 6, 4, 6, 7, 3, 3, 2, 5, 6, 6, 5, 6, 7, 5, 4, 3, 5. Create two R objects, one by the name "Sep", and the other by the name "Feb". The first object should contain the first data and the second object should contain the second data. Produce a frequency table (with the function "table") for each of the objects and a bar plot (with the combination of the function "plot" and the function "table"). For comparison, bar plots like the one you should obtain are presented in Figure 1.6. and Figure 1.7. In light of the description given above, and based on the tables and/or the plots, select the correct answer in each of the following 6 questions: Question 5 Correct Mark 1.00 out of 1.00 Flag question Question text The data used to produce the tables and plots is: Select one: a. A population. b. A sample. c. A parameter. d. A statistic. Feedback The meaning of deciding that the given information is a population is that one's target in the investigation of number of arriving calls is only with respect to the specific dates and times that are described in the question. It is more likely that one has a broader interest, say the overall workload of the department. In such a case the data represents number of incoming calls at other dates and times. Hence, it is a sample. A hint in favor of the option that the data is a subset of a larger population of phone-tracking information is the sentence: "The number of incoming calls between 8:00 AM and 8:10 AM in consecutive days were recorded." The correct answer is: A sample. Question 6 Correct Mark 1.00 out of 1.00 Flag question Question text The average number of calls that arrived between 8:00 AM and 8:10 AM during the working days of any month is: Select one: a. A population. b. A sample. c. A parameter. d. A statistic. Feedback The number of calls that arrived between 8:00 AM and 8:10 AM during the working days of any month in the context of this question is a population. Consequently, the average is a characteristic of the population, namely a parameter. A hint that the correct answer is a parameter and not a statistic is the fact that one cannot compute the value of the average from the data. The computation requires data from other months, which we do not have. The correct answer is: A parameter. Question 7 Correct Mark 1.00 out of 1.00 Flag question Question text The average number of calls recorded in the object "Feb" is 5.85. The average in the object "Sep" is 8.5. The difference between these two numbers is: Select one: a. A population. b. A sample. c. A statistic. d. None of the above. Feedback The difference between the averages is a characteristic of the data, a statistic. A hint that the correct answer is a statistic and not a parameter is the fact that one can compute the value of the average from the data. The correct answer is: A statistic. Question 8 Correct Mark 1.00 out of 1.00 Flag question Question text In which of the months the number of incoming calls between 8:00 AM and 8:10 AM tends to be smaller? Select one: a. September. b. February. c. The number of incoming calls in both months is about the same. d. One cannot answer the question based on the given data. Feedback The distribution in the month of February tends to concentrate in the range between 2 and 7. The distribution in the month of September tends to concentrate in the range between 6 and 10. The correct answer is: February. Question 9 Correct Mark 1.00 out of 1.00 Flag question Question text The height of the fourth bar from the left of the bar plot for the month of February represents the fact that? Select one: a. In 4 of the days of the month of February there were 5 incoming calls. b. In 5 of the days of the month of February there were 4 incoming calls. c. In 4 of the days of the month of February there were 2 incoming calls. d. In 2 of the days of the month of February there were 4 incoming calls.