Question 1

Based on a poll, a newspaper reported that between 54% and 62% of voters would be likely to vote for new county jail facility. What is the margin of error of the poll?
A) 4%
B) 8%
C) 27%
D) 31%

Accepted Answer

The margin of error is calculated as half the range of the reported percentages. The range is 62% - 54% = 8%, so the margin of error is 8% / 2 = 4%.

Question 2

Select the sample most representative of the population of interest
-An employer wanted to determine the importance of health insurance as a benefit to employees. Which sample is likely to be unbiased by personal interest?
A) A group of 30 employees from the company who had medical treatment in the past year
B) A survey of 300 union members conducted by the union that represents workers at the company.
C) A group of thirty potential employees at the state office of employment
D) All of the groups in A, B, and C have potential bias.

Accepted Answer

All of the groups have potential bias because they are not representative of the entire population of employees. Group A is biased because it only includes employees who have had medical treatment in the past year, which means that it is more likely to include employees who are concerned about health insurance. Group B is biased because it is conducted by the union, which represents workers at the company, which means that it is more likely to include employees who are in favor of health insurance. Group C is biased because it only includes potential employees, which means that it is more likely to include employees who are not currently employed and may not be aware of the importance of health insurance.

Question 3

Select the sample most representative of the population of interest
-A concerned parent wants to determine the amount of time spent on the phone by her child's friends.
A) The results of a national poll of 1800 students in the same age group as the child
B) The answers to the question by the parent(s) of 10 of the friends
C) The answers to the question by 10 of the friends
D) The phone records of 10 of the group of friends

Accepted Answer

The phone records of 10 of the group of friends provide objective data directly related to the specific group of interest, making it the most representative sample.

Question 4

Determine which evaluation guideline applies best in questioning the results of the described stud
-A teacher wanted to know the attitudes of faculty on early dismissal for Homecoming. She randomly selected 20 of the 114 faculty and asked them to circle "agree" or "disagree" on the form: "Agree/Disagree: Valuable learning time should not be sacrificed for extracurricular social activities.".
A) Consider the wording of any survey.
B) Consider the type of study.
C) Consider the form of response.
D) Consider the sampling method.

Accepted Answer

The wording of the survey can influence the responses, as it may lead respondents to a particular answer by framing the question in a biased way.

Question 5

Determine whether the given value is a statistic or parameter
-As shown in the Crime Watch article of the local newspaper, 37% of the crimes in the county in the month of September were crimes against property.
A) Statistic
B) Parameter

Accepted Answer

The value represents a parameter because it describes a characteristic of the entire population of crimes in the county for that month.

Question 6

A political pollster reports that his candidate has a 10% lead in the polls with 10% undecided.
A) Experimental
B) Observational

Accepted Answer

This is an observational method, as the pollster is simply observing and collecting data on the current state of the polls. There is no manipulation or intervention in this method.

Question 7

A bird bander captured seven ovenbirds in her mist net and found that the average length (from the tip of the bill to the end of the tail) was 5.86 inches.
A) Sample
B) Population

Accepted Answer

The bird bander captured and measured only a subset of all ovenbirds, making it a sample, not the entire population of ovenbirds.

Question 8

Identify the type of sampling used
-The name of each contestant is written on a separate card, the cards are placed in a bag and three names are picked from the bag.
A) Stratified
B) Systematic
C) Convenience
D) Random
E) Cluster

Accepted Answer

This is an example of random sampling, as each contestant's name is placed on a card, mixed in a bag, and then names are drawn without any specific order or pattern, giving each contestant an equal chance of being selected.

Question 9

Determine whether the statement is based on sample data or census data
-Based on a randomly selected group of 500 patients with diabetes, it was found that 67% are overweight.
A) Sample data
B) Census data

Accepted Answer

The statement is based on sample data because it refers to a randomly selected group of 500 patients, not the entire population of patients with diabetes.

Question 10

Of 540 college students interviewed, 360 said they were skeptical of statistical studies. The student conducting the study for the campus paper reported that between 15,000 and 17,000 of the 24,000 students on campus were skeptical of statistical studies. Which of the following is an acceptable alternative to the original report?
A) "Between 63% and 71% of students at the university are skeptical of statistical studies."
B) "Two of every three students on campus are skeptical of statistic studies."
C) "A total of 16,000 students on this campus are skeptical of statistical studies."
D) "If you are confident in the results of statistical studies, then the person on your left and the person on your right in every class are skeptical of the results of statistical studies."

Accepted Answer

The original report states that between 15,000 and 17,000 of the 24,000 students are skeptical, which translates to approximately 62.5% to 70.8%. Choice A correctly reflects this range in percentage terms.

Question 11

A biologist wants to determine the effect of a diet supplement using white rats. A shipment of 20 rats is obtained from a biological supply firm. They arrive in a single box. The biologist reaches into the box and the first ten rats caught are assigned to the control group and the remaining rats are assigned to the experimental group receiving the supplement. Select the potential source of confounding.
A) Method of formation of the control and treatment groups
B) Experimenter effect
C) Placebo effect
D) The study is essentially free from potential sources of confounding.

Accepted Answer

The answer of A biologist wants to determine the effect...

Question 12

Sixty-seven of the 156 students taking Introductory Statistics are business majors. Which question most probably represents the purpose of the study?
A) What percent of students take Introductory Statistics?
B) What percent of Introductory Statistics students are business majors?
C) What percent of business majors take Introductory Statistics?
D) What percent of students are business majors?

Accepted Answer

The study focuses on the proportion of business majors within the Introductory Statistics class, which is directly addressed by option B.

Question 13

A stock analyst selects a stock from a group of twenty for investment by choosing the stock with the greatest earnings per share reported for the last quarter.
A) Experimental
B) Observational

Accepted Answer

The stock analyst is observing existing data (earnings per share) to make a decision, rather than manipulating variables or conditions, which aligns with observational measurement.

Question 14

Determine whether the given value is a statistic or a parameter
-An investigation of 150 randomly selected local restaurants concluded that 42% of local restaurants have serious health code violations.
A) Statistic
B) Parameter

Accepted Answer

The value is a statistic because it is derived from a sample (150 randomly selected local restaurants) rather than the entire population of local restaurants.

Question 15

A U.S. government report stated that, "With bank interest rates at 3.0%, 21% of wage earners believe it worthwhile to keep money in a savings account. However, at 5.0% interest, 27% of wage earners believe it worthwhile to keep money in a savings account. The margin of error for both studies is 4 percentage points." The goal of the study
A) was to prove that higher interest rates encourage more people to save money.
B) is not clear from the report of the study.
C) was to determine the effect of an interest rate increase from 3% to 5% on the percentage of persons saving money.
D) was to determine the effect of interest rates on the percentage of persons saving money.

Accepted Answer

The answer of A U.S. government report stated that, "With...

Question 16

Identify the type of sampling used
-A tax auditor randomly selects 500 income tax returns from each of four income tax brackets.
A) Stratified
B) Systematic
C) Convenience
D) Random
E) Cluster

Accepted Answer

The sampling method used is stratified sampling because the auditor divides the population into different income tax brackets (strata) and then randomly selects samples from each bracket.

Question 17

Wisconsin had a recall vote for Governor in 2012 with Milwaukee Mayor Tom Barrett challenging the Republican Governor Scott Walker. A poll was conducted three weeks prior to the June election by surveying 520 randomly selected registered voters from the city of milwaukee. Each was contacted and asked to declare a Barrett or Walker preference electronically. The results showed that 421 of those in the sample showed a preference for barrett. The last step in the statistical study would be to
A) determine the population parameter and the margin of error.
B) examine the results for reasonableness or correctness.
C) review the study and see if the design was correct to meet the goal of the study.
D) publish the results of the study.

Accepted Answer

Reviewing the study to ensure the design was correct is crucial to validate that the study met its goals and that the results are reliable before publishing or making conclusions.

Question 18

Determine whether the statement is based on sample data or census data
-A researcher examines the records of all the registered voters in one city and finds that 43% are registered Democrats.
A) Sample data
B) Census data

Accepted Answer

The statement is based on census data because the researcher examined the records of all registered voters in one city, not just a sample of them.

Question 19

A county planner studying health insurance costs determined that the average age of 10 of the 37 sheriff's deputies was 48.6 years.
A) Sample
B) Population

Accepted Answer

The 10 deputies are a sample of the 37 total deputies, as they represent a subset of the entire group.

Question 20

Select the type of study most appropriate to the questio
-Is the aspirin produced by a particular pharmaceutical company better than that of a competitor at relieving headaches?
A) Case-controlled observational
B) Observational
C) Double blind experimental
D) Experimental

Accepted Answer

A double-blind experimental study is most appropriate as it eliminates bias by ensuring neither the participants nor the researchers know which product is being administered, allowing for a fair comparison of the effectiveness of the two aspirin products.

Quiz 1: Speaking of Statistics

Based on a poll, a newspaper reported that between 54% and 62% of voters would be likely to vote for new county jail facility. What is the margin of error of the poll?

Select the sample most representative of the population of interest -An employer wanted to determine the importance of health insurance as a benefit to employees. Which sample is likely to be unbiased by personal interest?

Select the sample most representative of the population of interest -A concerned parent wants to determine the amount of time spent on the phone by her child's friends.

Determine whether the given value is a statistic or parameter -As shown in the Crime Watch article of the local newspaper, 37% of the crimes in the county in the month of September were crimes against property.

A political pollster reports that his candidate has a 10% lead in the polls with 10% undecided.

A bird bander captured seven ovenbirds in her mist net and found that the average length (from the tip of the bill to the end of the tail) was 5.86 inches.

Identify the type of sampling used -The name of each contestant is written on a separate card, the cards are placed in a bag and three names are picked from the bag.

Determine whether the statement is based on sample data or census data -Based on a randomly selected group of 500 patients with diabetes, it was found that 67% are overweight.

Sixty-seven of the 156 students taking Introductory Statistics are business majors. Which question most probably represents the purpose of the study?

A stock analyst selects a stock from a group of twenty for investment by choosing the stock with the greatest earnings per share reported for the last quarter.

Determine whether the given value is a statistic or a parameter -An investigation of 150 randomly selected local restaurants concluded that 42% of local restaurants have serious health code violations.

Identify the type of sampling used -A tax auditor randomly selects 500 income tax returns from each of four income tax brackets.

Determine whether the statement is based on sample data or census data -A researcher examines the records of all the registered voters in one city and finds that 43% are registered Democrats.

A county planner studying health insurance costs determined that the average age of 10 of the 37 sheriff's deputies was 48.6 years.

Select the type of study most appropriate to the questio -Is the aspirin produced by a particular pharmaceutical company better than that of a competitor at relieving headaches?