chapter 1 intro to statistics terms – Flashcards
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"Fifty patients on dialysis are divided into two groups. One group receives an experimental drug to fight cancer, the other placebo. After two years, kidney functionality is measured." is this an observational study or experiment?
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The study is an experiment because the researchers control one variable to determine the effect on the response variable.
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What does it mean when sampling is done without replacement?
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Once an individual is selected, the individual cannot be selected again.
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What is frame?
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A frame is a list of individuals in the population being studied
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Determine if the underlined numerical value in following statement is a is a parameter or a statistic: "In a certain soccer league 6(underlined) of the 14 teams had won more games than they had lost."
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Parameter, because the data set of all 14 teams is a population.
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______" are the characteristics of the individuals of the population being studied
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Variables
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"____" is a numerical summary of a sample
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Statistic
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"_____" is a numerical summary of a population
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Parameter
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A "____" is a person or object that is a member of the population being studied
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Individual
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What's is a cross-sectional study?
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Cross sectional studies are observational studies that collect information about individuals at a specific point in time or over a very short period of time.
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What is a case-control study?
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case-control studies are observational studies that are retrospective, meaning that they require individuals to look back in time or require the researcher to look at existing records
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What is a superior observational study? ( cross-sectional or case-control)?
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Neither study is always superior to the other. Both have advantages and disadvantages that depend on the situation
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Determine if the following statement depicts an observational study or experiment... "A poll is conducted by a school's math department in which 9th grade students are asked if they prefer to be in their math class or their English class."
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The study is an observational study examines individuals in a sample, but does not try to influence the response variable.
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What is an observational study?
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An observational study measures the value of the response variable without attempting to influence the value of either the response or explanatory variables
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What is a design experiment?
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A design experiment is when a researcher assigns individuals to a certain group, intentionally changing the value of an explanatory variable, and then recording the value of the response variable for each group
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Which allows the researcher to claim causation between an explanatory variable and a response variable? A design experiment or observational study?
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A design experiment
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"____" statistics consists of organizing and summarizing information collected, while "____" statistics use methods that generalize results obtained from a sample to the population and measure the reliability of the results.
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"Descriptive", "inferential"
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Determine whether the given value is a statistic or a parameter: "in a study of all 4051 professors at a college, it is found that 40% own a television."
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It is a: Parameter because the value is a numerical measurement describing a characteristic of a population.
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Define statistics
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Statistics is the science of collecting, organizing, summarizing, and analyzing information to draw a conclusion and answer questions. In addition, statistics is about providing a measure of confidence in any conclusion.
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Determine whether the (underlined value) is a parameter or statistic. "The avg. age of men who had walked on the moon was (39 years, 11 months, 15 days).
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The value is a parameter because the men who had walked on the moon are a population.
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What does it mean when an observational study is retrospective?
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A retrospective study requires that individuals look back in time or require the researcher to look to existing records.
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What does it mean when an observational study is prospective?
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A prospective study collects the data over time.
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What is meant by confounding?
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Confounding in a study occurs when the effects of two or more explanatory variables are not separated. Therefore, any relation that may exist between an explanatory variable and the response variable may be due to some other variable or variables not accounted for in the study.
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What is a lurking variable?
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A lurking variable is an explanatory variable that was not considered in a study, but that affects the value of the response variable in the study. In addition, lurking variables are typically related to explanatory variables in the study.
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Determine whether the quantitative variable is discrete or continuous. "Passes made by a defenseman in a hockey game"
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The variable is discrete because it is countable
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Determine whether the study depicts an observational study or an experiment "Forty people are divided into two groups. One group is exposed to atonal classical music. The other is not. After one month, both groups are questioned about their ability to remember random phrases."
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The study is an experiment because the researchers control one variable to determine the effect on the response variable.
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Explain the difference between a single-blind and a double-blind experiment.
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In a single-blind experiment, the subject does not know which treatment is received. In a double-blind experiment, neither the subject not the researcher in contact with the subject knows which treatment is received.
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Determine the level of measurement of the variable below "Dress color"
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Nominal
