Question 1

A sample of five Fortune 500 companies showed the following industry codes: banking, banking, finance, retail, and banking. Based on this information, which of the following statements is correct?

Accepted Answer

The statement "Sixty percent of the sample of five companies are banking industries" is correct because 3 out of 5 of the sample companies are in the banking industry. None of the other statements can be concluded from the given information.

Question 2

Six hundred residents of a city are polled to obtain information on voting intentions in an upcoming city election. The six hundred residents in this study is an example of a(n)

Accepted Answer

The 600 residents polled in the study are a sample, which is a subset of the larger population (in this case, the population of the entire city). A census would involve surveying every single member of the population, which would be impractical and time-consuming. An observation would involve simply observing the behavior of individuals without any intervention, and in this case, the study involves actively polling individuals for their voting intentions. Therefore, the best answer is B) Sample.

Question 3

In a sample of 800 students in a university, 360, or 45%, live in the dormitories. The 45% is an example of

Accepted Answer

The 45% is a summary statistic that describes a characteristic of the sample, which is an example of descriptive statistics.

Question 4

A Scanner Data User Survey of 50 companies found that the average amount spent on scanner data per category of consumer goods was $387,325 (Mercer Management Consulting, Inc., April 24, 1997). The $387,325 is an example of

Accepted Answer

The average amount spent on scanner data is a numerical value, making it quantitative data. Additionally, it is also a descriptive statistic as it summarizes the data for a particular category of goods. Therefore, both D) quantitative data and a descriptive statistic are correct.

Question 5

Statistical inference

Accepted Answer

Statistical inference is the process of drawing conclusions about a population based on the information collected from a sample. It involves using sample statistics to make inferences about population parameters. Descriptive statistics, on the other hand, simply describe the characteristics of the sample itself. A census is a population count, which is different than statistical inference. Therefore, choice C is the best answer.

Question 6

The summaries of data, which may be tabular, graphical, or numerical, are referred to as

Accepted Answer

Descriptive statistics are used to summarize and describe the characteristics of a set of data, such as measures of central tendency (mean, median, mode) and measures of variability (range, standard deviation). Inferential statistics, on the other hand, involve making inferences or conclusions about a population based on a sample of data. Statistical inference refers to the process of using probability theory to make predictions or draw conclusions about a population based on a sample. Report generation refers to the process of creating a report or presentation of the data and analysis.

Question 7

Since a sample is a subset of the population, the sample mean

Accepted Answer

The sample mean can be larger, smaller, or equal to the mean of the population. It depends on the specific values within the sample and how representative they are of the entire population. Essentially, the sample mean provides an estimate of the population mean, but it may not be exactly the same value.

Question 8

A sample of five Fortune 500 companies showed the following revenues ($ millions): 7505.0, 2904.7, 7208.4, 6819.0, and 19500.0. Based on this information, which of the following statements is correct?

Accepted Answer

The sample mean of the given revenues is 10047.02 ($ millions). However, we cannot say that this is the average revenue for all Fortune 500 companies. But we can use this sample mean as an estimate of the population mean. Therefore, option A is the correct statement. Option B is incorrect because we cannot calculate the exact population mean with just a sample of five companies. Option C and D are also incorrect because we cannot make any reliable inference about the entire population based on just five companies.

Question 9

Since a sample is a subset of the population, a percentage that is calculated from the sample data

Accepted Answer

The percentage calculated from the sample data can be larger or smaller than the corresponding percentage from the population, depending on the variability of the sample and population. However, it is also possible for the two percentages to be equal if the sample is a representative subset of the population. Therefore, option D is the best choice.

Question 10

A statistics professor asked students in a class their ages. On the basis of this information, the professor states that the average age of all the students in the university is 21 years. This is an example of

Accepted Answer

This statement by the professor is an example of statistical inference because it is an estimation of a population parameter (average age of all students in the university) based on a sample (ages of students in the class).

Question 11

The average age in a sample of 90 students at City College is 20. As a result of this sample, it can be concluded that the average age of all the students at City College

Accepted Answer

Since the sample of 90 students is only a part of the entire student population at City College, it is possible that the average age of the entire population could be larger, smaller, or equal to 20. Therefore, choice D is the best answer.

Question 12

In a post office, the mailboxes are numbered from 1 to 5,000. These numbers represent

Accepted Answer

The answer of In a post office, the mailboxes are...

Question 13

The collection of all elements of interest in a particular study is

Accepted Answer

The population refers to the entire group of individuals, events, or other entities that the researcher is interested in studying. It is the collection of all elements of interest in a particular study.

Question 14

In a sample of 800 students in a university, 160, or 20%, are Business majors. Based on the above information, the school's paper reported that "20% of all the students at the university are Business majors." This report is an example of

Accepted Answer

The report is making a generalization about the entire university population based on the sample data, which is an example of statistical inference.

Question 15

The Department of Transportation of a city has noted that on the average there are 14 accidents per day. The average number of accidents is an example of

Accepted Answer

The average number of accidents is a descriptive statistic as it summarizes the characteristics of the data set (accidents in this case). Statistical inference involves making conclusions about a population based on a sample, whereas a population is the entire set of individuals or objects that one wants to study, and a sample is a portion of that population that is actually studied. None of these concepts apply to the given scenario.

Question 16

__________ is a spreadsheet package.

Accepted Answer

Microsoft Excel is a popular software package used for creating and working with spreadsheets.

Question 17

The process of analyzing sample data in order to draw conclusions about the characteristics of a population is called

Accepted Answer

Statistical inference involves using sample data to make conclusions and predictions about a larger population. Descriptive statistics is simply summarizing and describing the characteristics of the sample data, while data analysis and summarization are broader terms that can encompass both descriptive statistics and statistical inference.

Question 18

Dr. Kurt Thearling, a leading practitioner in the field, defines data mining as "the _________ extraction of _________ information from databases".

Accepted Answer

Dr. Kurt Thearling's definition emphasizes the use of automated processes to extract predictive information from databases, making option C the best fit for the missing words. Thorough and insightful (A) may be true, but are not emphasized in the definition. Timeliness (B) is not mentioned and accuracy alone is not enough to qualify as data mining. Intention (D) is not mentioned, and usefulness alone is not enough to qualify as data mining.

Question 19

The owner of a factory regularly requests a graphical summary of all employees' salaries. The graphical summary of salaries is an example of

Accepted Answer

The graphical summary of salaries is a type of descriptive statistic because it summarizes the data of all employees' salaries. Descriptive statistics are used to describe and summarize data, whereas statistical inference is used to draw conclusions about a population based on a sample. An experiment involves manipulating variables to test a hypothesis, which is not relevant to this scenario. Additionally, since the factory owner is requesting information on all employees' salaries, there is no sampling involved. Therefore, the graphical summary is not a sample.

Question 20

A portion of the population selected to represent the population is called

Accepted Answer

A sample is a subset of the population selected to represent it. The other choices refer to different aspects of statistics; statistical inference is the process of making predictions or generalizations about a population based on data from a sample, descriptive statistics are used to summarize and describe data, and a census is a complete count of a population.

Quiz 1: Data and Statistics