Ch. 2 - Collecting Data Sensibly.
An Introduction to Statistics and Data Analysis
Terms : Hide Images
| 6009303203 | Observational Study | Investigator observes characteristics of a subset an existing population(s) to draw conclusions relating to the differences between two or more populations. |  | 0 |
| 6009303204 | Survey | Interviewer seeks information from a respondent by engaging in a special type of conversation |  | 1 |
| 6009303205 | Experiment | Investigator observes how a response variable behaves when other explanatory variables (aka factors) are manipulated; factors should be determined by random assignment. |  | 2 |
| 6009303206 | Factors | Another name for the variables that researchers manipulate to create experimental conditions. |  | 3 |
| 6009303207 | Confounding Variable | A variable whose effect on the response variable cannot be distinguished from the effects of the treatment; if one is present it is impossible to draw cause and effect conclusions |  | 4 |
| 6009303208 | Random Sampling | Technique that allows every member of a population an equal probability of being selected for the sample; allows generalizations from a sample to a population. |  | 5 |
| 6009303209 | Census | Data is collected on every member of a population |  | 6 |
| 6009303210 | Selection Bias | A sample systematically excludes part of the population of interest; also called undercoverage |  | 7 |
| 6009303211 | Measurement Bias | Observed values systematically differ from the actual values; may occur due to improper calibration or leading surveying questions or techniques; also known as response bias |  | 8 |
| 6009303212 | Nonresponse Bias | Responses are not obtained from all individuals selected for inclusion in a sample; limited when the response rate is high and/or serious efforts to follow up with non-respondents are used |  | 9 |
| 6009303213 | Simple Random Sample (SRS) | Sample chosen using a method that ensures that each different possible SAMPLE of the desired SIZE has an equal chance of being chosen |  | 10 |
| 6009303214 | Sampling Frame | A list that is used to select a random sample; typically a random number table or generator is used to select the sample. |  | 11 |
| 6009303215 | Sampling with Replacement | Individuals can potentially be selected more than one time since they are returned to the pool of potential subjects after each selection |  | 12 |
| 6009303216 | Sampling without Replacement | Individuals can only be selected once since they are not returned to the pool of potential subjects after each selection |  | 13 |
| 6009303217 | Stratified Sampling | A method of dividing a population into non-overlapping homogenous subgroups and then selecting a SRS from EACH subgroup |  | 14 |
| 6009303218 | Cluster Sampling | A method dividing a population into non-overlapping heterogeneous subgroups and then random selecting entire subgroups; used to save time and money |  | 15 |
| 6009303219 | Systematic Sampling | A procedure that selects one of the first k individuals at random and then every k-th individual in the sequence is included in the sample; list of items must contain no repeating patterns |  | 16 |
| 6009303220 | Voluntary Response Sampling | Sample suffers from selection bias because only people with strong opinions choose to participate in the survey |  | 17 |
| 6009303221 | Convenience Sampling | Sample suffers from selection bias because subjects are chosen without regard to whether they are representative of a population |  | 18 |
| 6009303222 | Experimental Condition | Any particular combination of values for the explanatory variables; aka a treatment |  | 19 |
| 6009303223 | Design | The overall plan for conducting an experiment; should limit confounding variables and extraneous factors to achieve conclusive results |  | 20 |
| 6009303224 | Extraneous Factor | A variable that is not of interest in the current study but is thought to affect the response variable. |  | 21 |
| 6009303225 | Blocking | Filters out extraneous factors , by creating subgroups that are homogenous with respect to those factors, and then randomly assigns subjects from each subgroup to all treatment and/or control groups |  | 22 |
| 6009303226 | Confounded | When two or more factors effects on the response varaible cannot be distinguished from one another. | | 23 |
| 6009303227 | Blocks | Homogenous subgroups used to ensure that all experimental groups are similar in regards to one or more extraneous factor(s) |  | 24 |
| 6009303228 | Randomization | Used to ensure extraneous factors that can not be controlled through blocking or direct control are equally likely to occur in any experimental group |  | 25 |
| 6009303229 | Replication | The design strategy of making multiple observations for each experimental condition. |  | 26 |
| 6009303230 | Control Group | The group in an experiment that does not receive the experimental treatment; receives either the current standard treatment or no treatment at all |  | 27 |
| 6009303231 | Placebo | An object that is identical in appearance, taste, feel etc. to the treatment received by the treatment group, except that it contains no active ingredients. |  | 28 |
| 6009303232 | Placebo effect | Experimental results caused by expectations alone; any effect on behavior caused by the administration of an inert condition, which is assumed to be an active agent |  | 29 |
| 6009303233 | Single Blind | An experiment in which subjects do not know the treatment that they have received but the individuals measuring the response do know or occasionally vice-versa. |  | 30 |
| 6009303234 | Double Blind | An experiment where neither the subjects or the individuals who measure the response know which treatment was received. |  | 31 |
| 6009303235 | Experimental Unit | The smallest unit to which the treatments (which are assigned at random) are applied. |  | 32 |
| 6009565854 | Strata | Homogenous subgroups used to ensure that all characteristics of a population are represented by a random sample |  | 33 |
| 6009755425 | Direct Control | Filters out extraneous factors by ensuring that experimental conditions are constant for all subjects in regard to these factors |  | 34 |
