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Definition
| based on haphazardly selected individual cases which often come to our attention because they are strinking in some way. |
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| datat wat was producted in the past for some other purpose but that may help answer a present question |
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| exploratory data analysis |
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| explores or looks for general trends and potential relationships in data set that already exist. |
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| formal statistical inference |
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Definition
| used when we want to answer specific questions with a known degree of confidence |
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| the entire group of units or individuals about which we desire information |
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| the part of the population selected to be measured or observed in order to gather data for analysis |
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| an individual person, animal or object upon which the response variable or variable of interest is measured (if human-subject) |
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| explains or causes changes in the response variable |
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| measures an outcome of a study |
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| simple random sample (SRS) |
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Definition
| a sample that is selected from the population in such a way that every SRS of n units has an equal chance of being selected. (pulling names out of a hat...) |
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Definition
| a sample in which the population is divided into groups of similar units/individuals and a SRS is chosen seperately from each group. |
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| a sample in which successively smaller groups within the population are selected in stages. typically used when the population is so latge that it is too difficult to get the entire list. |
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| capture-recapture sampling design |
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Definition
| type of repeated SRS sampling biologists use to estimte the size of animal populations and also by the gov't when estimating number of households in an area. |
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Definition
| occurs when the sample systematically favors certain parts of the population over others. (can be due to undercoverage or nonresponse) |
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| occurs when some groups in the population are left out of the process of choosing the sample |
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| occurs when an individual chosen for the sample can't be contacted or does not cooperate |
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| occurs when the behavior of the respondent or interviewer changes the sample results (the respondent lies, the interviewer influences responses...) |
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| observes individuals and measures variables of interest but does not attempt to infuence the responses (survery) |
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Definition
| deliberatly imposes some reatment on individuals in order to observe their responses. |
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| the individuals on which the experiment is done |
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| a specific experimental condition applied to the units |
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| explanatory variable in an experiment |
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| the specific values of the factors which will be used |
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| what is being measured on each unit/subject |
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| a patient respons favorably to being treated, not to the treatment itself (your mind tricks you into getting better even though the med has no effect) |
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Definition
| the study systematically favors certain outcomes |
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Definition
| rely on chance to divide experimental units into groups that does not depend on any characterstic of the experimental units and that does not rely on the judgment of the experimenter in any way |
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Definition
| use enough experimental units to reduce chance variation |
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| completely randomized design |
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Definition
| all experimental units are divided at random among all treatments |
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Term
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Definition
| seperating out groups of experimental units or subjects that are known before the experiment to be similar in some way that is expecte to affect the response to treatments, nother form of control. |
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Term
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Definition
1. choose pairs of subjects that are closely matched
2. all subjects receive both treatments in random order |
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