Question 1

When testing a new treatment, what is the difference between statistical significance and practical significance? Can a treatment have statistical significance, but not practical significance?

Accepted Answer

Statistical significance is achieved when the result is very unlikely to occur by chance. Practical significance is related to whether common sense suggests that the treatment makes enough of a difference to justify its use. It is possible for a treatment to have statistical significance, but not practical significance.

Question 2

A transportation survey is conducted by an organization that prefers private automobiles over public transportation. What potential bias could this introduce?

Accepted Answer

There does appear to be a potential to create a bias. There is an incentive to produce results that are in line with preferring private automobiles.

Question 3

A study collects brain volumes from 10 pairs of monozygotic (identical) twins. The data were collected by researchers at Harvard University, Massachusetts General Hospital, Dartmouth College, and the University of California at Davis. Is there a potential for bias in this study?

Accepted Answer

There does not appear to be a potential to create a bias. The organizations collecting the data are reputable.

Question 4

In a study of a weight loss program, 6 subjects lost an average of 41 lbs. Methods of statistics can be used to show that if this diet had no effect, there is a 39% chance of getting these results by random chance. Does the weight loss program have statistical significance?

Accepted Answer

No, the program is not statistically significant because the results are likely to occur by chance.

Question 5

Does the weight loss program described above have practical significance?

Accepted Answer

Yes, the program is practically significant because the amount of lost weight is large enough to be considered practically significant.

Question 6

Refer to the sample of body temperatures (degrees Fahrenheit) at 8 AM and 12 AM for 8 subjects. What issue can be addressed by conducting a statistical analysis of the data?

Accepted Answer

The data can be used to address the issue of whether there is a correlation between body temperatures at 8 AM and at 12 AM.

Question 7

Several studies showed that after eating 4 servings of dairy a day, subjects had lowered risk of osteoporosis. The dairy farmer's organization financed this research. Identify what is wrong.

Accepted Answer

It is questionable that the sponsor is a dairy farmer's organization because this sponsor can be greatly affected by the conclusion.

Question 8

Which of the following is typically the least important factor to consider when conducting a statistical analysis of data?

Accepted Answer

Contact of the data

Question 9

Determine whether the underlined number is a statistic or a parameter. In a study of all 5426 seniors at a college, it is found that 40% own a vehicle.

Accepted Answer

Parameter because the value is a numerical measurement describing a characteristic of a population.

Question 10

Determine whether the data described below are qualitative or quantitative and explain why. The prices of a gallon of gasoline at the gas stations of a certain city.

Accepted Answer

The data are quantitative because they consist of counts or measurements.

Question 11

The sinking of the Titanic on April 15, 1912, is one of the most infamous disasters in history. A population of 1503 passengers and crew died when the Titanic sank approximately 400 miles south of Newfoundland, Canada. Identify whether the given value is a statistic or a parameter.

Accepted Answer

The value is a parameter because it describes some characteristic of a population.

Question 12

State whether the data described below are discrete or continuous, and explain why. The lengths of carrots produced by a farm.

Accepted Answer

The data are continuous because the data can take on any value in an interval.

Question 13

Determine which of the four levels of measurement (nominal, ordinal, interval, ratio) is most appropriate for the data: Favorite musicians.

Accepted Answer

Nominal

Question 14

Determine which of the four levels of measurement (nominal, ordinal, interval, ratio) is most appropriate for the data: Volume of planets in cubic meters.

Accepted Answer

The ratio level of measurement is most appropriate because the data can be ordered, differences $$a - b$$ obtained by subtraction $$a - b$$ can be found and are meaningful, and there is a natural starting point.

Question 15

Determine which of the four levels of measurement (nominal, ordinal, interval, ratio) is most appropriate for the data: Social security numbers.

Accepted Answer

The nominal level of measurement is most appropriate because the data cannot be ordered.

Question 16

Determine which of the four levels of measurement (nominal, ordinal, interval, ratio) is most appropriate for the data: Voltage measurements of batteries, such as 1.5 V, 4.5 V, 6 V, and 7.5 V.

Accepted Answer

Ratio

Question 17

Which of the following is NOT a level of measurement?

Accepted Answer

Quantitative

Question 18

Which of the following is associated with a parameter?

Accepted Answer

Data that were obtained from an entire population.

Question 19

A defunct website listed the "average" annual income for Florida as $35,031. What is the role of the term average in statistics? Should another term be used in place of average?

Accepted Answer

The term average is often used in statistics to represent the mean.

Fundamental Concepts and Applications in Introductory Statistics

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