Question 1

Jessica Salas, President of Salas Products, is reviewing the warranty policy for her company's new model of automobile batteries.Life tests performed on a sample of 100 batteries indicated an average life of seven years under normal usage.Jessica recommended a six-year warranty period for the new model.This is an example of _____________.

Accepted Answer

Jessica is using data from a sample (the life tests on 100 batteries) to make a decision about the warranty period for all batteries of the new model. This process of using sample data to make decisions or predictions about a larger group (the population) is an example of inferential statistics.

Question 2

Sue Taylor, Director of Global Industrial Sales, is concerned by a deteriorating sales trend. Specifically, the number of customers is stable at 1,500, but they are purchasing less each year.
She orders her staff to search for causes of the downward trend by selecting a focus group of 40 industrial customers.Sue is ordering a __________.

Accepted Answer

Sue is ordering a sample of the industrial customers because she is selecting a smaller group (40 industrial customers) out of the total population (1,500 customers) to study and gather information.

Question 3

The process of summarizing sample data is called

Accepted Answer

Descriptive statistics is the branch of statistics that involves summarizing and organizing data so it can be easily understood.

Question 4

On discovering an improperly adjusted drill press, Jack Joyner, Director of Quality Control, ordered a 100% inspection of all castings drilled during the evening shift.Jack is ordering a ___________________.

Accepted Answer

Jack is ordering a census of the castings because he is asking for an inspection of all castings drilled during the evening shift, which means every single item is being examined, not just a sample.

Question 5

Using data from a group to generalize to a larger group involves the use of _______.

Accepted Answer

Inferential statistics involve using data from a sample to make inferences or generalizations about a larger population. This contrasts with descriptive statistics, which aim to summarize or describe characteristics of the data in the sample itself.

Question 6

Sue Taylor, Director of Global Industrial Sales, is concerned by a deteriorating sales trend. Specifically, the number of customers is stable at 1,500, but they are purchasing less each year.
She orders her staff to search for causes of the downward trend by surveying all 1,500 industrial customers.Sue is ordering a __________.

Accepted Answer

Sue is ordering a census because she is asking for information from every member of the population (all 1,500 industrial customers), not just a subset.

Question 7

A new sales person is paid a commission on each sale.This person made $2,000 in commission his first month on the job.From this he concludes that he will make $24,000 during his first year.This is an example of _______.

Accepted Answer

This is an example of inferential statistics because the salesperson is using data from one month to make a prediction (or inference) about his earnings for the entire year. Inferential statistics involve making predictions or inferences about a population based on a sample of data.

Question 8

On discovering an improperly adjusted drill press, Jack Joyner, Director of Quality Control, ordered an inspection of every fifth casting drilled during the evening shift.Jack is ordering a ___________________.

Accepted Answer

Jack is ordering a sample of the castings because he is asking for an inspection of every fifth casting, which means he is selecting a subset of all the castings to inspect, not the entire population.

Question 9

The Chamber of Commerce wants to assess its membership's opinions of the North American Free Trade Agreement.One-hundred of the 2,000 members are randomly selected and contacted by telephone.Seventy-five reported an overall favorable opinion, and twenty-five reported an overall unfavorable opinion.The proportion, 0.75, is a ___________.

Accepted Answer

The proportion of 0.75 represents a statistic because it is a summary measure calculated from a sample (the 100 members contacted) of the larger population (the 2,000 members of the Chamber of Commerce).

Question 10

Pinky Bauer, Chief Financial Officer of Harrison Haulers, Inc., suspects irregularities in the payroll system, and orders an inspection of "each and every payroll voucher issued since January 1, 2013." Pinky is ordering a __________________.

Accepted Answer

Pinky is ordering a census of the payroll vouchers because she wants an inspection of "each and every payroll voucher," which means examining the entire set of data without selecting a subset or sample.

Question 11

On discovering an improperly adjusted drill press, Jack Joyner, Director of Quality Control, ordered an inspection of every fifth casting drilled during the evening shift.Less than 1% of the sampled castings were defective; so, Jack released the evening shift's production to assembly.This is an example of _______________.

Accepted Answer

Jack used a sample (every fifth casting) to make an inference about the entire production of the evening shift, which is a core principle of inferential statistics.

Question 12

Pinky Bauer, Chief Financial Officer of Harrison Haulers, Inc., suspects irregularities in the payroll system, and orders an inspection of "every tenth payroll voucher issued since January 1, 2013." Pinky is ordering a __________________.

Accepted Answer

Pinky is ordering a sample of the payroll vouchers because selecting "every tenth payroll voucher" is a method of sampling, not examining the entire population (census) or organizing (sorting) the vouchers.

Question 13

A student makes an 82 on the first test in a statistics course.From this, she estimates that her average at the end of the semester (after other tests)will be about 82.This is an example of _______.

Accepted Answer

The student is using the score from one test (a sample) to make an estimate about her overall performance (the population mean) for the semester, which is an example of inferential statistics.

Question 14

The Universal Pulp Company has a plant in Portland, Oregon.Management wants to determine the average number of sick days taken per worker in this plant in 2018.To do this, management gathers records on all the workers in the plant and averages the number of sick days taken in 2018 by each worker.This process is using _______.

Accepted Answer

The answer of The Universal Pulp Company has a plant...

Question 15

A market researcher is interested in determining the average income for families in Duval County, Florida.To accomplish this, she takes a random sample of 400 families from the county and uses the data gathered from them to estimate the average income for families in the entire county.This process is an example of _______.

Accepted Answer

This process is an example of inferential statistics, where a sample is used to make inferences or predictions about a larger population.

Question 16

A local manufacturing plant randomly selected 200 items from a production run and 9 of them are defective.The proportion of defective items in this sample is a ________.

Accepted Answer

The proportion of defective items in this sample is a statistic because it is a numerical measure that describes an aspect of a sample.

Question 17

The Magnolia Swimming Pool Company wants to determine the average number of years it takes before a major repair is required on one of the pools that the company constructs.The president of the company asks Rick Johnson, a company accountant, to randomly contact fifty families that built Magnolia pools in the past ten years and determine how long it was in each case until a major repair.The information will then be used to estimate the average number of years until a major repair for all pools sold by Magnolia.The average based on the data gathered from the fifty families can best be described as a _______.

Accepted Answer

The average based on data gathered from the fifty families is a statistic because it is a summary measure calculated from a sample drawn from a larger population.

Question 18

A cancer research group was interested in determining the percentage of women 40 years or older that have regularly scheduled mammograms.To accomplish this, they surveyed 500 women in this age group and based on the 155 women that responded affirmatively, estimated the percentage of all women in this age group that have regularly scheduled mammograms.This process is an example of _________.

Accepted Answer

The process described is an example of inferential statistics, where a sample (the 155 women who responded affirmatively out of the 500 surveyed) is used to make inferences or estimates about the larger population (all women 40 years or older regarding their mammogram schedules).

Question 19

Miguel Hernandez, Senior Vice President of Human Resources at Memorial Hospital is exploring the usage of nursing overtime hours in the emergency department during the last operating year.Staffing records and emergency department visits for all 365 days between the period of January 1, 2018, and December 31, 2018, are selected for analysis.Miguel's collection method can best be classified as a

Accepted Answer

Miguel's method is a census because he is examining data from every single day of the operating year, not just a subset or sample of those days.

Question 20

What proportion of San Diego's registered voters favors trade restrictions with China? In an effort to determine this, a research team calls every registered voter in San Diego and contacts them.The proportion determined from the data gathered is a _______.

Accepted Answer

Since the research team contacts every registered voter in San Diego, the proportion determined is a parameter, as it reflects the entire population of interest.

Quiz 1: Introduction to Statistics and Business Analytics