question test on statistic Flashcards
(48 cards)
Part 1
In an AOL survey of Internet users, this question was posted online: “Have you ever been hit by a computer virus?” Among the 170,063 responses, 63% answered “yes.” What term is used to describe this type of survey in which the people surveyed consist of those who chose to respond? What is wrong with this type of sampling method?
What term is used to describe this type of survey? Select all that appl
What is wrong with this type of sampling method? Select all that apply.
A.
The respondents are a self-selected sample.
B.
The respondents are a voluntary response sample.
A.
The respondents are a self-selected sample.
B.
The respondents are a
D.
Many people may choose not to respond to the survey.
E.
Responses may not reflect the opinions of the general population.
.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?
C.
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.
Determine whether the given source has the potential to create a bias in a statistical study.
A data set includes 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
C.
There does not appear to be a potential to create a bias. The organizations collecting the data are reputable.
Determine whether the given source has the potential to create a bias in a statistical study.
An article in Journal of Nutrition (Vol. 130, No. 8) noted that chocolate is rich in flavonoids. The article notes “regular consumption of foods rich in flavonoids may reduce the risk of coronary heart disease.” The study received funding from Mars, Inc., the candy company, and the Chocolate Manufacturers Association.
c.
The researchers may have been more inclined to provide favorable results because funding was provided by a party with a definite interest. The bias could have been avoided if the researchers were not paid by the candy company and the chocolate manufacturers.
Determine whether the sampling method described below appears to be sound or is flawed.
In a survey of subjects, the following question was posted on a newspaper’s website: “In your view, are nuclear plants safe?” The survey subjects were Internet users who chose to respond to the question posted on the electronic edition of the newspaper.
A.
It is flawed because it is a voluntary response sample.
Determine whether the results below appear to have statistical significance, and also determine whether the results have practical significance.
In a study of a weight loss program, subjects lost an average of lbs. It is found that there is about a % chance of getting such results with a diet that has no effect.
Does the weight loss program have practical significance?
D.
No, the program is not statistically significant because the results are likely to occur by chance.
C.
Yes, the program is practically significant because the amount of lo
Determine whether the results appear to have statistical significance, and also determine whether the results appear to have practical significance.
One of a botanist’s hybridization experiments with peas yielded 500 offspring with 128 of those peas (or 26%) having yellow pods. According to genetic theory, 25% of the offspring peas should have yellow pods.
Does the result have statistical significance?
According to genetic theory,
(125)* of the (500)* peas would have yellow pods. The difference between the actual number of peas with yellow pods and the expected number of peas with yellow pods is
(3 )pea(s). This difference (does not appear)
to be statistically significant.
(Type whole numbers.)
Part 2
Does the result have practical significance?
This difference
(does not appear)*
to have practical significance, because the difference between the actual number of peas with yellow pods and the expected number of peas with yellow pods is
(very small)*
compared to the actual number of peas with yellow pods.
Determine whether the underlined number is a statistic or a parameter.
In a study of all 3849 seniors at a college, it is found that 50% own a television.
Parameter because the value is a numerical measurement describing a characteristic of a population.
Determine whether the data described below are qualitative or quantitative and explain why.
Determine whether the data described below are qualitative or quantitative and explain why.
The preferred hands of an experiment’s participants.
The data are qualitative because they don’t measure or count anything.
State whether the data described below are discrete or continuous, and explain why.
The numbers of hotel in cities.
The data are discrete because the data can only take on specific values.
Determine wether the given value is a statistic or a parameter.
A homeowner measured the voltage supplied to his home on 323 days of given year, and the average (mean) Value is 107.6 volts.
The given value is a statistic for the year because the data collected represent a sample.
The sinking of the titanic on April 15, 1912, is one of the most infamous disaster in history. A population of 1503 passenger 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.
The value is a parameter because it describes some characteristic of a population.
In study of a sample of babies born at hospitals in one state, it was found that the average (mean) weight at birth was 3134.2 grams. Identify whether this value is a statistic or a parameter.
The Value is a statistic because it describe some characteristic of a sample.
State whether the data described below are discrete or continuos, and explain why.
The exact heights of different elephants.
The data are continuous because the data can take on any value in an interval.
State whether the data described below are discrete or continuous, and explain why.
The numbers of teeth that different animal have
The data are discrete because the data can only on specific value.
State whether the data described below are discrete or continuous, and explain why.
The exact length ( in centimeters) of different fish found in a lake
The data are continuous because the data can take on any value in an interval.
Determine which of the four levels of measurement ( nominal, ordinal, interval, ratio) is most appropriate.
C. Nominal
Determine which of the four levels of measurement ( nominal, ordinal, interval, ratio) is most appropriate for the data below.
Brands of toothpaste
A. The nominal level of measurement is most appropriate because the data cannot be ordered.
Determine which of the four levels of measurement (nominal, ordinal, interval, ratio) is most appropriate for the data below.
Years in which U.S. presidents were inaugurated
The interval level of measurement is most appropriate because the data can be ordered, differences can be found and are meaningful, and there is no natural starting zero point.
Determine which of the four levels of measurement (nominal, ordinal, interval, ratio) is most appropriate for the data below.
Course grades from A to F.
The ordinal level of measurement is most appropriate because the data can be ordered, but differences cannot be found or are meaningless.
Determine which of the four levels of measurement (nominal, ordinal, interval, ratio) is most appropriate for the data below.
People’s ages
The ratio level of measurement is most appropriate because the data can be ordered, difference (obtained by subtraction) can be found and are meaningful, and there is a natural starting zero point.
Determine which of the for levels of measurement (nominal, ordinal, interval, ratio) is most appropriate
Ages of children: 4,5,6,7, and 8
Ratio
Identify the level of measurement of the data, and explain what is wrong with the given calculation.
In surgery, the responses of respondents are identified as 100 for a “yes”, 200 for “no”, 300 for a “maybe” and 400 for anything else. The average (mean) is calculated for 525 respondents and the result is 256.1.
Such data are not counts or measurement of anything, so it makes no sense to compute their average (mean).
