STAT 193 – Chapter One – Flashcards
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Which of the following situations is an example of an observational study?
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II. On cold days, you record which of your classmates come to school without a jacket. Later, you record how many of those students become sick. You take notes and observe at a local gym your fellow members who go outside with a wet head and notice if they are sick when they return to the gym at a later date.
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Sample surveys such as the General Social Survey and the Current Population Survey are an important kind of:
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Observational Study
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The Gallup Poll is an example of a(n):
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Sample Survey
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What is the difference between a census and a sample survey?
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A census attempts to include the entire population in the survey whereas a sample survey only studies some of the members of the population.
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Which of the above situations is an example of an experiment?
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III. You find 30 adults and divide them into two groups. The first group is told not to wear jackets on cold days, the other group is told to wear jackets on cold days. You then compare the number from each group who get sick after a string of cold days.
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The difference between an experiment and an observational study is:
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An observational study tries to gather information without interfering; an experiment looks to actively impose a treatment to see how they respond.
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Statistics
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Is the tool for extracting information from data. Focus on the Key concept Statistics is all about dealing with uncertainty The Interested in making statements about a population
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Population
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The collection of people, items, or quantities of interest, but because we can't possibly characterize the entire population in most cases, we have to sample from the population and base our statements on those sample data.
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Sample Data
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Use to infer characteristics of populations The key element for statistic are estimation, hypothesis testing, and prediction,
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Estimation
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Is the process of approximating the value of population parameters (using either point or interval estimates) For example we want to know the average fish that live in a particular lake, the fish in the lake is the population and the parameters is the average fish weight.
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3 Key Concepts of Statistics
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*Probability *Sampling Distribution *Inference
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Probability
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is the foundation for all of statistics
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Sampling Distribution
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Are key to unlocking the really powerful aspects of statistics, the ability to make inference or make statements with confidence about population parameters
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Sample
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A part of a population used to describe the whole group * random sampling * simple random sampling *cluster sampling *stratified sampling *systematic sampling
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Parameter
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the characteristics used to describe a population >are numbers that summarize data for an entire population. & Statistics are numbers that summarize data from a sample,
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Statistics
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is the science of data, it's collection, analysis, and interpretation
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Variable
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A variable is any characteristics, number, or quantity that can be measured or counted. A variable may also be called a data item. Age, sex, business income and expenses, country of birth, capital expenditure, class grades, eye colour and vehicle type are examples of variables http://www.abs.gov.au/websitedbs/a3121120.nsf/home/statistical+language+-+what+are+variables
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Uncertainty
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something that is uncertain or that causes one to feel uncertain.
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Individuals
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are the objects described by a set of data. Individuals may be people, but they may also be animals or things
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Variable
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is any characteristic of an individual. A variable can take different values for different individuals
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Statistics
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deals with numbers, but not all variables are numerical. Some are categorical and simply place an individual into one of several groups or categories
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Census
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A sample survey that attempts to include the entire population in the sample.
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Bureau
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an office or department for transacting particular business a government department agency: provides a service, like an aid organization or a government bureau.
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Causation (Experience)
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the action of causing something.
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Association (Observation)
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(often in names) a group of people organized for a joint purpose.
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Observation Study
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observes individuals and measures variables of interest but does not intervene in order to influence the response. A study that observes individuals and measures variables of interest, yet does not involve any intervention that will influence the responses. The purpose of such a study is to describe some group or situation
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Experience
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Anyone impose a treatment that determine a cause and effect
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Obervation
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At first, the observer may not know what to record. Eventually, patterns seem to emerge and we can decide what variable we want o measure.
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Response
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a variable that measures an outcome or result of a study
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Sample
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The part of the population from which we collect information and is used to draw conclusions about the whole
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Population
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In a statistical study, this is the entire group of individual about which we want information
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Preelection Poll
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A sample survey that asks people how they will vote in the future. Because people often change their minds before the election, these polls are not very reliable
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Census
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Attempts to measure every individual in a population
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Experiments
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actually do something to individuals in order to see how they respond. The goal of an experiment is usually to learn whether some treatment actually causes a certain response
