Question 1

Following the Republican National Convention, a poll of 600 voters in a Central Illinois community showed that 57% expected the Republican ticket to win over the Democrat ticket no matter whom the Democrats chose for vice-president. The margin of error was 4 percentage points. There are 25,000 registered voters in the community. What is the range likely to contain the population parameter?

Accepted Answer

The range likely to contain the population parameter is the poll percentage plus or minus the margin of error, which is 57% ± 4%, resulting in a range of 53% to 61%.

Question 2

Identify the type of sampling used
-A sample consists of every 49th student from a group of 496 students.

Accepted Answer

In systematic sampling, every nth element is selected from a list or sequence, which is the case here with every 49th student being chosen.

Question 3

A marketing firm does a survey to find out how many people use a product. Of the one hundred people contacted, fifteen said they use the product.

Accepted Answer

The survey is observational because it involves collecting data without manipulating any variables or conditions.

Question 4

Select the sample most representative of the population of interest
-A college student who does laundry infrequently wants to determine the effect of bluing on what should be white clothes.

Accepted Answer

Using two loads of personal wash, one with bluing and one without, allows the student to directly compare the effect of bluing on their own clothes, minimizing variability and ensuring the sample is representative of their specific laundry habits.

Question 5

A poll of 488 citizens of Normal, Illinois showed that 65% favored strict enforcement of speed limits with a margin of error of 4%. A second poll of 495 citizens of the same town showed that 34% favored strict enforcement of speed limits. Assuming that proper sampling techniques were used in both polls, one may conclude that

Accepted Answer

The significant difference in results between the two polls suggests that one or both samples may not accurately represent the population, possibly due to sampling variability or other factors.

Question 6

A nutritionist wants to conduct a study to validate the efficacy of an herb as an aid in weight loss. She randomly assigns half of a group of overweight persons to a treatment group who are given the herb with instructions for its use and a planned diet for six weeks. The other half of the group is given parsley with the same instructions and same diet. A nurse at the nutrition center weighs each subject on Friday of each week. Select the potential source of confounding.

Accepted Answer

The answer of A nutritionist wants to conduct a study...

Question 7

After taking the first exam, 15 of the students dropped the class.

Accepted Answer

The population is the entire group of students who took the first exam. The sample is the 15 students who dropped the class after taking the first exam.

Question 8

Determine whether the statement is based on census data or sample data
-A researcher determines that 17% of 84 property owners in a large city are behind in their tax payments.

Accepted Answer

The statement is based on sample data because it refers to a subset (84 property owners) of a larger population (all property owners in the city).

Question 9

Two samples of fish are taken from a river upstream and downstream of a factory to measure the effect of pollution from the factory on the fish.

Accepted Answer

This is an observational study because the researchers are observing and measuring the effect of pollution without manipulating any variables or conditions.

Question 10

Select the type of study most appropriate to the question
-Which is the best fertilizer for Mr. Jimenez' backyard grass?

Accepted Answer

An experimental study is most appropriate to determine the best fertilizer for Mr. Jimenez' backyard grass because it allows the researcher to control the variables and isolate the effects of the fertilizer.

Question 11

To avoid working late, a quality control analyst simply inspects the first 100 items produced in a day.

Accepted Answer

The analyst is using convenience sampling by inspecting the first 100 items, as it is the easiest and quickest method without randomization or systematic selection.

Question 12

A researcher determines that 42.7% of all downtown office buildings have ventilation problems.

Accepted Answer

The researcher is referring to all downtown office buildings, which constitutes the entire population. Therefore, the answer is population.

Question 13

Determine whether the given value is a statistic or a parameter
-A researcher determines that 42.7% of all downtown office buildings have ventilation problems.

Accepted Answer

The value represents a parameter because it describes a characteristic of the entire population of downtown office buildings.

Question 14

A student wanted to know the favorite lunch at a large high school with a closed campus. What is the first step in conducting a statistical study to answer the question?

Accepted Answer

The first step in conducting a statistical study is to clearly define the goal or objective of the study to ensure that the research is focused and relevant.

Question 15

The average age of all 63 Associate Professors at Cliffton University is found to be 47 years.

Accepted Answer

The average age of all 63 Associate Professors at Cliffton University represents the entire group, making it a population.

Question 16

A poll of 700 persons attending the Taste of Chicago showed that 455 persons, 65% of the sample, believed that the food was overpriced. It is estimated that 1,250,000 persons attend the Taste. Statistics suggest that, although 65% plus or minus 5% of attendees believe that the food is overpriced, the Taste is a popular event. The raw data of the study is (are)

Accepted Answer

The raw data refers to the actual numbers collected in the study, which are 700 persons surveyed and 455 persons who believed the food was overpriced.

Question 17

Select the sample most representative of the population of interest
-The father of a junior high school student wants to determine the most popular book among junior high students. Select the sample with the least potential bias.

Accepted Answer

A randomly selected group of 30 junior high students is most representative of the population of interest, as it is likely to include a diverse range of students without the biases present in the other options.

Question 18

Determine which evaluation guideline applies best in questioning the results of the described study
-A homeowner put a brand-name fertilizer/weed killer on half of his lawn and a generic fertilizer/weed killer on the other half. After three weeks, the generic side had 1 weed per square meter, the other side 1.7 weeds per square meter. The generic side required two mowings in the 3 weeks, the brand-name side one. The homeowner concluded that the generic was superior to the brand-name.

Accepted Answer

The study may have confounding variables, such as differences in sunlight, soil quality, or watering patterns, that could affect the results independently of the fertilizer/weed killer used.

Question 19

Which data provide the answer to the question: "How frequently can a student at Eureka College be expected to study more than three hours a day?".

Accepted Answer

Of 100 students surveyed, 43 reported that they study at least three hours a day twice a week. This data provides the answer to the question: "How frequently can a student at Eureka College be expected to study more than three hours a day?".

Question 20

Determine whether the statement is based on census data or sample data
-The average age of all 63 Associate Professors at Cliffton University is found to be 47 years.

Accepted Answer

The statement refers to the average age of all 63 Associate Professors at Cliffton University, indicating that data was collected from the entire population of interest, making it census data.

Quiz 1: Speaking of Statistics

Identify the type of sampling used -A sample consists of every 49th student from a group of 496 students.

A marketing firm does a survey to find out how many people use a product. Of the one hundred people contacted, fifteen said they use the product.

Select the sample most representative of the population of interest -A college student who does laundry infrequently wants to determine the effect of bluing on what should be white clothes.

After taking the first exam, 15 of the students dropped the class.

Determine whether the statement is based on census data or sample data -A researcher determines that 17% of 84 property owners in a large city are behind in their tax payments.

Two samples of fish are taken from a river upstream and downstream of a factory to measure the effect of pollution from the factory on the fish.

Select the type of study most appropriate to the question -Which is the best fertilizer for Mr. Jimenez' backyard grass?

To avoid working late, a quality control analyst simply inspects the first 100 items produced in a day.

A researcher determines that 42.7% of all downtown office buildings have ventilation problems.

Determine whether the given value is a statistic or a parameter -A researcher determines that 42.7% of all downtown office buildings have ventilation problems.

A student wanted to know the favorite lunch at a large high school with a closed campus. What is the first step in conducting a statistical study to answer the question?

The average age of all 63 Associate Professors at Cliffton University is found to be 47 years.

Select the sample most representative of the population of interest -The father of a junior high school student wants to determine the most popular book among junior high students. Select the sample with the least potential bias.

Which data provide the answer to the question: "How frequently can a student at Eureka College be expected to study more than three hours a day?".

Determine whether the statement is based on census data or sample data -The average age of all 63 Associate Professors at Cliffton University is found to be 47 years.