The following vocabulary terms are related to experiments and samples in statistics.
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| 7997832139 | Population of interest | the entire group of individuals or instances whom we hope to learn | 0 | |
| 7997832140 | randomization | the best defense against bias: each individual is given a fair, equal chance of selection | 1 | |
| 7997832141 | sample | a representative subset of a population, examined in hope of learning about the population | 2 | |
| 7997832142 | representative sample | A sample that accurately reflects the characteristics of the population as a whole | 3 | |
| 7997832143 | census | A sample that consists of the entire population | 4 | |
| 7997832144 | bias | any systematic failure of a sampling method to represent its population. | 5 | |
| 7997832145 | population parameter | a numerically valued attribute of a model for a population | 6 | |
| 7997832146 | simple random sample | A sample selected in such a way that every element in the population or sampling frame has an equal probability of being chosen AND all samples of size n have an equal chance of being selected. | 7 | |
| 7997832147 | stratified random sample | a sampling design in which the population is divided into several subpopulations, and random samples are then drawn from each stratum | 8 | |
| 7997832148 | cluster sample | Divide the population into smaller groups each which is representative of the entire population. Randomly select some of the groups. All of the members in these selected groups will make up the sample. | 9 | |
| 7997832149 | systematic sample | A sample drawn by selecting individuals using a randomly selected starting point and a fixed periodic interval. This interval, called the sampling interval, is calculated by dividing the population size by the desired sample size. (e.g., every 5th person) | 10 | |
| 7997832150 | voluntary response bias | bias introduced to a sample when individuals can choose on their own whether to participate in the sample | 11 | |
| 7997832151 | convenience sample | A convenience sample consists of the individuals who are conveniently available. Convenience samples often fail to be representative because every individual in the population is not equally convenient to sample. | 12 | |
| 7997832152 | blinding | Any individual associated with an experiment who is not aware of how subjects have been allocated to treatment groups. | 13 | |
| 7997832153 | block | when groups of experimental units are similar and share a characteristic that may influence their response to a treatment, units or subjects are first divided into homogeneous groups due to their similar traits | 14 | |
| 7997832154 | confounding | Two variables are associated in a way that it is difficult to determine which variable (the explanatory variable or some other variable) is causing an effect on the response variable. | 15 | |
| 7997832155 | control group | In an experiment, the group that is not exposed to the treatment; contrasts with the experimental group and serves as a comparison for evaluating the effect of the treatment. May receive a null or placebo treatment | 16 | |
| 7997832156 | designs | all experimental units have an equal chance of receiving any treatment | 17 | |
| 7997832157 | experiment | manipulates factor levels to create treatments: randomly assigns subjects to these treatment levels, and then compares the responses of the subject groups across treatment levels | 18 | |
| 7997832158 | single blind | An experiment in which subjects do not know whether they are in the experimental or control group. | 19 | |
| 7997832159 | double blind | An experiment in which neither the subjects nor the people who work with them know which treatment each subject is receiving | 20 | |
| 7997832160 | experimental units | individuals on whom an experiment is performed | 21 | |
| 7997832161 | factor | a variable who's levels are manipulated by the experimenter | 22 | |
| 7997832162 | level | the specific values that an experimenter chooses for a factor | 23 | |
| 7997832163 | lurking variable | A variable that we are not aware of may have an effect on the response in an experiment. Random assignment is used to attempt to equally distribute these variables among different treatment groups. | 24 | |
| 7997832164 | observational study | A study that merely observes conditions of individuals in a population and records information; the population is disturbed as little as possible. (Note: treatments are not imposed on units.) | 25 | |
| 7997832165 | placebo | A fake treatment given to the control group to control participant expectancy | 26 | |
| 7997832166 | placebo effect | the tendency of many human subjects to show a response even when administered a placebo | 27 | |
| 7997832167 | Principles of experimental design | control, randomize, and replicate | 28 | |
| 7997832169 | random assignment | an experiment must assign experimental units to treatment groups at random to account for possible confounding or lurking variables | 29 | |
| 7997832170 | replication | using enough experimental units or subjects to achieve meaningful results | 30 | |
| 7997832171 | response | a variable whose values are compared across different treatment | 31 | |
| 7997832174 | treatment | the process, intervention, or other controlled circumstance applied to randomly assigned experimental units. | 32 | |
| 7997832175 | matched pairs testing | homogeneous pairs are established and the treatment is randomly assigned to one experimental unit or subject within each pair. | 33 | |
| 7997832176 | randomized block design | Start by forming blocks consisting of individuals that are similar in some way that is important to the response. Random assignment of treatments is then carried out separately within each block. | 34 | |
| 7997832177 | completely randomized design | subjects are randomly assigned to different treatment or control groups | 35 | |
| 7997832178 | population | the entire group of individuals or items that we are interested in | 36 | |
| 7997832180 | sampling error | Inherent flaws in the design of the sample itself, such as undercoverage | 37 | |
| 7997832181 | sample survey | process of collecting information from a sample | 38 | |
| 7997832182 | census | process of collecting information from all the units in a population - it's feasible but often requires a huge amount of work, time, and money | 39 | |
| 7997832183 | observational study | the experimenter OBSERVES the relationships among variables rather than creating them | 40 | |
| 7997832184 | convenience sampling | biased; sampling that's easy to obtain | 41 | |
| 7997832185 | volunteer sampling | biased; subjects choose to be part of the sample | 42 | |
| 7997832186 | simple random sampling | process of obtaining a sample from a population in which each member has an equal chance of being selected | 43 | |
| 7997832187 | systematic sampling | first item is selected at random from the first k items in the frame, then every kth item is included in the sample | 44 | |
| 7997832188 | stratified random sampling | population is divided into strata and a simple random sample is selected from each stratum | 45 | |
| 7997832189 | strata | homogeneous groups of populations units (those in one stratum have similar in some characteristics, while those in another stratum differ from those characteristics) | 46 | |
| 7997832190 | sampling variability | differences in responses and results inherent in any survey or sample | 47 | |
| 7997832191 | response bias | caused by the behavior of the interviewer or respondent | 48 | |
| 7997832192 | nonresponse bias | the person selected for an interview cannot be contacted or refuses to answer. This is an example of non-sampling error. | 49 | |
| 7997832193 | undercoverage bias | part of the population is left out of the selection process. This is an example of sampling error. | 50 | |
| 7997832194 | wording bias | confusing or leading questions are asked | 51 | |
| 7997832197 | cause and effect | Only with a well-designed experiment are we able to justify that one variable is responsible for influencing an outcome in a response variable. | 52 |
