Chapter 1
Identify which type of sampling is used. To determine customer opinion of their pricing, Home Depot randomly selects 110 check out lines during a certain week and surveys all customers in the check out lines.
Cluster
Divide the population area into sections (or clusters), then randomly select some of those clusters, and choose all the members from those selected clusters.
Cluster sampling
Identify the type of sampling used . A man experienced a tax audit. The tax department claimed that the man was audited because everyone in four randomly selected districts was being audited
Cluster sampling
Determine whether the data described below are qualitative or quantitative and explain why. The types of climates for different regions left tropical comma temperate comma arid comma etc.
The data are qualitative because they don't measure or count anything.
Determine whether the data described below are qualitative or quantitative and explain why. The times of birth of babies born at a certain hospital
The data are quantitative because they consist of counts or measurements.
Determine whether the data described below are qualitative or quantitative and explain why. The numbers of cases of flu treated at a certain hospital in different years
The data are quantitative because they consist of counts or measurements.
a technique in which the subject doesn't know whether he or she is receiving a treatment or a placebo. _____ is a way to get around the placebo effect
Blinding
consists of numbers representing counts or measurements
quantitative
Determine whether the value given below is from a discrete or continuous data set. The volume of cola in a can is 10.8 oz.
A continuous data set because there are infinitely many possible values and those values cannot be counted
Determine whether the results appear to have statistical significance, and also determine whether the results appear to have practical significance. In a study of a gender selection method used to increase the likelihood of a baby being born a girl, 1924 users of the method gave birth to 941 boys and 983 girls. There is about a 17% chance of getting that many girls if the method had no effect.
Because there is a 17% chance of getting that many girls by chance, the method does not have statistical significance. Not many couples would likely use a procedure that raises the likelihood of a girl from the approximately 50% rate expected by chance to the 51% produced by this method. So this method does not have practical significance.
Identify which type of sampling is used. A television station asks its viewers to call in their opinion regarding the variety of sports programming.
Convenience
Identify the type of sampling used in the situation below. A woman is selected by a marketing company to participate in a paid focus group. The company says that the woman was selected because her name is among the first 300 in the phone number listings.
Convenience sampling
Use data that are very easy to get.
Convenience sampling
Determine whether the value is from a discrete or continuous data set. Number of coins in a jar is 78
Discrete
The subject doesn't know whether he or she is receiving the treatment or a placebo. The experimenter does not know whether he or she is administering the treatment or placebo.
Double-Blind
apply some treatment and then proceed to observe its effects on the individuals. (The individuals in experiments are called experimental units, and they are often called subjects when they are people.)
Experiment
involves data that can be arranged in order, and the differences between data values can be found and are meaningful. However, there is no natural zero starting point at which none of the quantity is present. differences but no natural zero point
Interval level
what is a problem with a very low response rate?
It creates a serious potential for getting a biased sample that consists of those with a special interest in the topic
Determine whether the sampling method described below appears to be sound or is flawed. In a survey of 511 subjects, each was asked how often he or she played sports. The survey subjects were internet users who responded to a question that was posted on a news website.
It is flawed because it is a voluntary response sample
Determine whether the sampling method described below appears to be sound or is flawed. In a survey of 586 subjects, each was asked how often he or she played sports. The survey subjects were internet users who responded to a question that was posted on a news website
It is flawed because it is a voluntary response sample
Several studies showed that when eating a diet low in red meat, subjects had decreased cholesterol. High cholesterol levels have been associated with increased risk of heart disease and stroke. A poultry farmer's organization financed this research. Identify what is wrong.
It is questionable that the sponsor is a poultry farmer's organization because this sponsor can be greatly affected by the conclusion.
Collect data by using some combination of the basic sampling methods. In ____, pollsters select a sample in different stages, and each stage might use different methods of sampling.
Multistage sampling
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, 6 subjects lost an average of 47 lbs. It is found that there is about a 34% chance of getting such results with a diet that has no effect.
No the program is not statistically significant because the results are likely to occur by chance. Yes it is practically significant because the amount of lost weight is large enough to be considered practically significant
Determine which of the four levels of measurement (nominal, ordinal, interval, ratio) is most appropriate. Favorite types of music
Nominal
characterized by data that consist of names, labels, or categories only, and the data cannot be arranged in some order (such as low to high).
Nominal level
Determine whether the description corresponds to an observational study or an experiment. Research is conducted to determine if there is a relation between Parkinson's disease and childhood head trauma.
Observational
observing and measuring specific characteristics without attempting to modify the individuals being studied
Observational study
Determine which of the four levels of measurement (nominal, ordinal, interval, ratio) is most appropriate. Livability rankings for cities
Ordinal
involves data that can be arranged in some order, but differences (obtained by subtraction) between data values either cannot be determined or are meaningless. categories with some order
Ordinal level
a numerical measurement describing some characteristic of a population
Parameter
Determine whether the given value is a statistic or a parameter. In a study of all 4492 employees at a college comma it is found that 40 % own a television.
Parameter because the value is a numerical measurement describing a characteristic of a population
Determine whether the given value is a statistic or a parameter. In a study of all 4020 seniors at a college, it is found that 25 % own a television.
Parameter because the value is a numerical measurement describing a characteristic of a population.
occurs when an untreated subject reports an improvement in symptoms
Placebo effect
result when the data values are quantitative and the number of values is finite, or "countable." Can take on only particular, distinct values and not other values in between
discrete data
Identify which type of sampling is used. A large company wants to administer a satisfaction survey to its current customers. Using their customer database, the company randomly selects 60 customers and asks them about their level of satisfaction with the company.
Random
Identify the type of sampling used in the situation. In a poll conducted by a certain research center, 942 adults were called after their telephone numbers were randomly generated by a computer, and 52 % were able to correctly identify the attorney general.
Random sampling
Determine which of the four levels of measurement (nominal, ordinal, interval, ratio) is most appropriate. Ages of children: 3, 4, 5, 6, and 7
Ratio
data can be arranged in order, differences can be found and are meaningful, and there is a natural zero starting point (where zero indicates that none of the quantity is present). Differences and ratios are both meaningful. differences and a natural zero point
Ratio level
A sample of n subjects is selected in such a way that every possible sample of the same size n has the same chance of being chosen. _____ is often called a random sample, (but strictly speaking, a random sample has the weaker requirement that all members of the population have the same chance of being selected)
Simple random sample
Determine whether the sampling method described below appears to be sound or is flawed. In a survey of 780 human resource professionals, each was asked about the importance of the age of a job applicant. The survey subjects were randomly selected by pollsters from a reputable market research firm.
Sound because the data are not biased
a numerical measurement describing some characteristic of a sample
Statistic
Determine whether the given value is a statistic or a parameter. A sample of professors is selected and it is found that 40 % own a television.
Statistic because the value is a numerical measurement describing a characteristic of a sample
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?
Statistical significance is achieved when the result is very unlikely to occur by chance. (likelihood of occurring by chance is 5% or less) Practical significance is related to whether common sense suggests that the treatment makes enough of a difference to justify its use.
Determine whether the given value is a statistic or a parameter. A sample of students is selected and it is found that 45 % own a television.
Statistics because the value is a numerical measurement describing a characteristic of a sample.
Identify which of these types of sampling is used. To determine her heart rate, Carolyn divides up her day into three parts: morning, afternoon, and evening. She then measures her heart rate at 4 randomly selected times during each part of the day.
Stratified
Identify which sampling is used. A market researcher has partitioned all residents of a certain region into categories of unemployed comma employed full time comma and employed part time. She is surveying 59 people from each category.
Stratified
Subdivide the population into at least two different subgroups (or strata) so that the subjects within the same subgroup share the same characteristics. Then draw a sample from each subgroup (or stratum).
Stratified sampling
Identify the level of measurement of the data, and explain what is wrong with the given calculation. In a survey, the hair colors of respondents are identified as 0 for brown hair, 1 for blond hair, 2 for black hair, and 3 for anything else. The average (mean) is calculated for 716 respondents and the result is 1.1 .
Such data are not counts or measures of anything, so it makes no sense to compute their average (mean).
Identify the type of sampling used. To estimate the percentage of defects in a recent manufacturing batch, a quality control manager at General Electric selects every 17th refrigerator that comes off the assembly line starting with the fifth until she obtains a sample of 30 refrigerators.
Systematic
Identify the type of sampling used (random, systematic, convenience, stratified, or cluster sampling) in the situation described below. A researcher selects every 721 social security number and surveys the corresponding person.
Systematic sampling
Select some starting point and then select every kth element in the population
Systematic sampling
Identify the level of measurement of the data, and explain what is wrong with the given calculation. In a set of data, alert levels are represented as 1 for low, 2 for medium, and 3 for high. The average (mean) of the 783 alert levels is 1.3 . What is wrong with the given calculation?
The data are at the ordinal level of measurement, Such data should not be used for calculations such as an average
State whether the data described below are discrete or continuous, and explain why. The volumes left (in cubic feet) of different rooms
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 weights of dogs left parenthesis in pounds right parenthesis at a dog show
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 number of people in a theater each night
The data are discrete because the data can only take on specific values.
State whether the data described below are discrete or continuous, and explain why. The number of pieces of mail a person receives each day
The data are discrete because the data can only take on specific values.
State whether the data described below are discrete or continuous, and explain why. The numbers of different sizes offered by various clothing manufacturers
The data are discrete because the data can only take on specific values.
State whether the data described below are discrete or continuous, and explain why. The numbers of living grandparents that different people have
The data are discrete because the data can only take on specific values.
State whether the data described below are discrete or continuous, and explain why. The numbers of typos in different students' essays
The data are discrete because the data can only take on specific values.
Determine whether the given description corresponds to an observational study or an experiment. In a study of 388 women with a particular disease, the subjects were photographed daily.
The given description corresponds to an observational study
Determine whether the given value is a statistic or a parameter. A homeowner measured the voltage supplied to his home on all 365 days of a given year, and the average (mean) value is 144.7 volts.
The given value is a parameter for the year because the data collected represent a population.
Determine whether the given value is a statistic or a parameter. A homeowner measured the voltage supplied to his home on 30 different days, and the average (mean) value is 116.9 volts.
The given value is a statistic for the year because the data collected represent a sample.
In a study, 1643 patients were randomly assigned to one of three groups: (1) the 547 subjects in the placebo group; (2) 550 subjects were in a group given meds to take regularly; (3) 546 subjects were in a group given pills with the medication to be taken when needed. In what way was replication applied in the study?
The group sample sizes are all large so the researchers could see the effects of the treatment
Determine which of the four levels of measurement is most appropriate for the data below. Body temperature in degrees Fahrenheit
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. Eye colors
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. Survey responses of "yes comma " "no comma " and "no opinion"
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. Ranks of cars evaluated by a consumer's magazine
The ordinal level of measurement is most appropriate because the data can be ordered but differences cannot be found or are meaningless.
Determine if the following statement represents a meaningful ratio, so the ratio level of measurement applies. A movie with a 4-star rating is twice as good as one with a 2-star rating
The ratio level of measurement does not apply
Determine which of the four levels of measurement is most appropriate for the data below. Number of houses people own
The ratio level of measurement is most appropriate because the data can be ordered, differences left (obtained by subtraction) can be found and are meaningful, and there is a natural starting zero point.
Determine which of the four levels of measurement (nominal, ordinal, interval, ratio) is most appropriate for the data below. Volume of planets in cubic meters
The ratio level of measurement is most appropriate because the data can be ordered, differences left parenthesis obtained by subtraction right parenthesis can be found and are meaningful, and there is a natural starting zero point.
A newspaper posted this question on its website: "How often do you seek medical information online?" Of 1072 Internet users who chose to respond, 38% of them responded with "frequently." What term is used to describe this type of survey in which the people surveyed consist of those who decided to respond? What is wrong with this type of sampling method? What term is used to describe this? Whats wrong with this sampling method?
The respondent are a voluntary response sample and are a self-selected sample. Many people may choose not to respond, responses may not reflect the opinions of the general population
A particular country has 55 total states. If the areas of all 55 states are added and the sum is divided by 55, the result is 205 comma 412 square kilometers. Determine whether this result is a statistic or a parameter.
The result is a parameter because it describes some characteristic of a population.
A magazine ran a survey about a web site for downloading music. Readers could register their responses on the magazine's web site. what is wrong?
The sample is a voluntary response sample, so there is a good chance that the results do not reflect the population.
Determine whether the given value is a statistic or a parameter. A study was conducted of all 2524 car owners in a certain country.
The value is a Th parameter because it is a numerical measurement describing some characteristic of a population.
Determine whether the source given below has the potential to create a bias in a statistical study. A certain medical organization tends to oppose the use of meat and dairy products in our diets, and that organization has received hundreds of thousands of dollars in funding from an animal rights foundation.
There does appear to be bias. There is an incentive to produce results that are in line with the organization's creed and that of its funders
Is it possible for treatment to have statistical significant and not practice?
Yes
result from infinitely many possible quantitative values, where the collection of values is not countable. Can take on any value in a given interval
continuous data
Identify the type of sampling used (random, systematic, convenience, stratified, or cluster sampling) in the situation A woman is selected by a marketing company to participate in a paid focus group. The company says that the woman was selected because her name is among the first 250 in the phone number listings.
convenience sampling
Quantitative data can be further described by distinguishing between
discrete and continuous types
In a study of 355 students with a particular disease, the subjects were monitored with an EEG while asleep. Does the given description correspond to an observational study or an experiment?
observational study
Categorical data consists of names or labels (not numbers that represent counts or measurements).
qualitative data
Identify the type of sampling used (random, systematic, convenience, stratified, or cluster sampling) in the situation A researcher selects every 768 th social security number and surveys the corresponding person.
systematic sampling
Determine if the following statement represents a meaningful ratio, so the ratio level of measurement applies. A movie with a 4-star rating is twice as good as one with a 2-star rating.
the ratio level of measurement does not apply
