Question 1

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
A)a census
B)descriptive statistics
C)an experiment
D)statistical inference

Accepted Answer

This is an example of statistical inference because the professor is using a sample (the students in their class) to make an inference about the population (all students in the university).

Question 2

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
A)categorical data
B)quantitative data
C)a descriptive statistic
D)Both quantitative data and a descriptive statistic are correct.

Accepted Answer

The given value ($387,325) represents a numerical quantity and thus is quantitative data. Additionally, it provides descriptive information about the amount spent on scanner data per category of consumer goods and hence is a descriptive statistic.

Question 3

A portion of the population selected to represent the population is called
A)statistical inference
B)descriptive statistics
C)a census
D)a sample

Accepted Answer

A portion of the population selected to represent the population is known as a sample. The other options are not correct definitions for this term. Descriptive statistics refers to the analysis and interpretation of data collected from a population or sample. Statistical inference is the process of using data from a sample to make conclusions about a larger population. A census is an attempt to collect data from every member of a population, whereas a sample only includes a portion of the population.

Question 4

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?
A)An estimate of the average revenue for all Fortune 500 companies is 8787.42 ($ millions).
B)The average revenue for all Fortune 500 companies is 8787.42 ($ millions).
C)Over half of all Fortune 500 companies earn at least 7208.4 ($ millions) in revenues.
D)If five other Fortune 500 companies were chosen, the average revenue would be 8787.42 ($ millions).

Accepted Answer

We can find the estimate of the average revenue for all Fortune 500 companies by taking the sum of the revenues of the five companies and dividing it by the number of companies, which is 5.

Average revenue = (7505.0 + 2904.7 + 7208.4 + 6819.0 + 19500.0) / 5 = 8787.42 ($ millions)

Note that we cannot say for certain that the average revenue for all Fortune 500 companies is exactly 8787.42 ($ millions) since we only have a sample of five companies.

Question 5

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
A)must be more than 20, since the population is always larger than the sample
B)must be less than 20, since the sample is only a part of the population
C)could not be 20
D)could be larger, smaller, or equal to 20

Accepted Answer

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

Question 6

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
A)a sample
B)a population
C)statistical inference
D)descriptive statistics

Accepted Answer

The answer of In a sample of 800 students in...

Question 7

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)
A)census
B)sample
C)observation
D)population

Accepted Answer

The six hundred residents are a subset of the larger population (which would likely include all eligible voters in the city), making them a sample. A census would involve collecting data from every member of the population, which is typically not feasible or necessary in most research studies. Observation refers to the process of collecting data through direct observation of behavior or events, which is not what is happening in this scenario. The population is the entire group being studied, which in this case would include all eligible voters in the city, not just the 600 residents being polled.

Question 8

Since a sample is a subset of the population, a percentage that is calculated from the sample data
A)is always smaller than the corresponding percentage from the population
B)is always larger than the corresponding percentage from the population
C)must be equal to the corresponding percentage from the population
D)can be larger, smaller, or equal to the corresponding percentage from the population

Accepted Answer

The percentage calculated from a sample data can be larger, smaller or equal to the corresponding percentage from the population because the sample may not always perfectly represent the population. Therefore, it is possible for the calculated percentage to differ from the actual percentage in the population.

Question 9

__________ is a spreadsheet package.
A)Statistical inference
B)The bar chart
C)The New York Stock Exchange
D)Microsoft Excel

Accepted Answer

Microsoft Excel is a widely used spreadsheet package for performing data analysis and manipulation. The other options (statistical inference, bar chart, New York Stock Exchange) are not spreadsheet packages.

Question 10

Since a sample is a subset of the population, the sample mean
A)is always smaller than the mean of the population
B)is always larger than the mean of the population
C)must be equal to the mean of the population
D)can be larger, smaller, or equal to the mean of the population

Accepted Answer

The sample mean can be larger, smaller, or equal to the mean of the population. It will depend on the particular sample that was selected from the population. Thus, option D is the correct answer.

Question 11

The summaries of data, which may be tabular, graphical, or numerical, are referred to as
A)inferential statistics
B)descriptive statistics
C)statistical inference
D)report generation

Accepted Answer

Descriptive statistics are summaries of data that provide information about the central tendency, variability, and distribution of a dataset. Inferential statistics, on the other hand, involve making predictions or generalizations about a larger population based on a sample of data. Statistical inference is the process of using inferential statistics to make these predictions or generalizations. Report generation refers to the creation of a report or document that presents the results of a statistical analysis.

Question 12

The process of analyzing sample data in order to draw conclusions about the characteristics of a population is called
A)descriptive statistics
B)statistical inference
C)data analysis
D)data summarization

Accepted Answer

Statistical inference involves using sample data to make conclusions about a larger population, which is exactly what is being described in the question. Descriptive statistics, data analysis, and data summarization are all important steps in this process, but they do not capture the full scope of what is being asked in the question.

Question 13

The collection of all elements of interest in a particular study is
A)the population
B)the sampling
C)statistical inference
D)descriptive statistics

Accepted Answer

The population refers to the entire group of individuals or objects that researchers are interested in studying. This is the group that researchers want to make inferences about using statistical methods.

Question 14

In a sample of 800 students in a university, 360, or 45%, live in the dormitories. The 45% is an example of
A)a sample
B)a population
C)statistical inference
D)descriptive statistics

Accepted Answer

45% is a descriptive statistic, which is a summary measure of a sample. It describes the proportion of the sample who live in the dormitories. A population refers to the entire group of interest, while statistical inference involves making generalizations about a population based on a sample.

Question 15

The owner of a factory regularly requests a graphical summary of all employees' salaries. The graphical summary of salaries is an example of
A)a sample
B)descriptive statistics
C)statistical inference
D)an experiment

Accepted Answer

The graphical summary of salaries is an example of descriptive statistics as it involves summarizing and describing the data, without making any inferences or predictions about the population.

Question 16

In a post office, the mailboxes are numbered from 1 to 5,000. These numbers represent
A)categorical data
B)time series data
C)either categorical or quantitative data
D)quantitative data

Accepted Answer

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

Question 17

Dr. Kurt Thearling, a leading practitioner in the field, defines data mining as "the _________ extraction of _________ information from databases".
A)thorough, insightful
B)timely, accurate
C)automated, predictive
D)intentional, useful

Accepted Answer

Dr. Kurt Thearling's definition of data mining emphasizes the automated nature of the process and its focus on predicting or extracting useful information. Therefore, the best choice is C, which includes both of these aspects. A, B, and D do not fully capture the essence of data mining as defined by Thearling.

Question 18

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
A)descriptive statistics
B)statistical inference
C)a sample
D)a population

Accepted Answer

The average number of accidents is an example of descriptive statistics, which summarizes and describes the characteristics of a specific data set. Statistical inference refers to using sample data to make generalizations about a larger population. A sample is a subset of a larger population, and a population refers to the entire group of individuals or objects that the researcher is interested in studying. None of these concepts apply to the given scenario, as the average number of accidents is simply a statistic describing a specific data set.

Question 19

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?
A)Sixty percent of the sample of five companies are banking industries.
B)Sixty percent of all Fortune 500 companies are banking industries.
C)Banking is the most common type of industry among all Fortune 500 companies.
D)If five other Fortune 500 companies were chosen, 60% of them would be banking industries.

Accepted Answer

The correct statement is that 60% of the sample of five companies are banking industries. We cannot make any inference about the percentage of all Fortune 500 companies that are in the banking industry based on this small sample. We also cannot determine if banking is the most common type of industry among all Fortune 500 companies since we only have information on five companies. Finally, we cannot make a prediction about the future sample of five Fortune 500 companies based on this small sample.

Question 20

Statistical inference
A)refers to the process of drawing inferences about the sample based on the characteristics of the population
B)is the same as descriptive statistics
C)is the process of drawing inferences about the population based on the information taken from the sample
D)is the same as a census

Accepted Answer

Statistical inference is the process of drawing conclusions about the population based on information gathered from a sample. Descriptive statistics, on the other hand, is the process of summarizing and describing the characteristics of the sample itself. A census refers to collecting data from an entire population, while statistical inference typically involves working with a sample of that population. Therefore, choice C is the best answer.

Quiz 1: Data and Statistics

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

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

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

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?

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

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

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)

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

__________ is a spreadsheet package.

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

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

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

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

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

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

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

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

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

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?

Statistical inference