Is a variable that attempts to explain differences among responses.

Is a data collection activity in which the experimenter merely plays the role of an observer.

Such a bias that occurs due to the behavior of the interviewer or respondent.

Is the entire group of individuals or items in a study.

Forms the probabilistic basis for statistical inference.

A list (or comparable form of identification) of all members of a population.

Is the number of times a treatment appears in an experiment, or the number of experimental units to which each treatment is applied in an experiment.

Is said to be present when one factor produces a different pattern of responses at one level of a second factor than it does at another level.

Plays a vital role in the selection of samples that represent the population and hence produce good approximations.

All experimental units are grouped by certain characteristics to form homogeneous blocks, and a completely randomized design is applied within each block.

The differences among the average (mean) productivity of workers assigned to the four treatments may be a result of differences among these four treatments.

This is sometimes called the dependent variable.

A __ is __ if it tends to give samples in which some characteristic of the population is underrepresented or overrepresented.

Is a process of obtaining a sample from a population in which each sample of size n has an equal chance of being selected.

The method of measurement should be designed to produce the most accurate data possible and should be free of this.

A sample is collected and studied to gain information about a population.

Is a variable whose effect on the response cannot be separated from the effect of the treatments.

Is the smallest unit (person, animal, building, item, etc.) to which a treatment is applied.

Is a planned activity designed to compare “treatments.”

May occur if confusing or leading questions are asked.

Is used to control the effects of factors that you can control easily.

It is up to individuals to decide whether they want to be part of the survey.

The population to which we intend to apply the results of the study.

Is a group of homogeneous (similar in characteristics) experimental units.

Are the values of a factor used in the experiment.

May occur if part of the population is left out of the selection process.

Occurs when variables are measured incorrectly.

May occur if the person selected for the interview cannot be contacted or refuses to answer.

Is the part of a population that is actually studied.

Virtually any sampling scheme that depends upon subjective judgments rather than randomization as to who (or which item) should be included in the sample will suffer from this.

The differences among the productivities of workers assigned to the same treatment measure.

This approach uses no probability and is entirely based on the judgment of the person selecting the sample.

Are homogeneous groups of population units.

Means complete enumeration.

If there are only two treatments to be compared in each block.

Is the outcome of interest to be measured in an experiment.

These result in values that are systematically different from the population values, or systematically favor certain outcomes, resulting in systematic overestimation or underestimation.

Instead of using his expertise to select spots for getting soil samples, suppose an engineer takes soil samples from the easily accessible areas.

Are the factor-level combinations used in the experiment.

If a population is divided into homogeneous strata and a simple random sample is selected from each stratum.

Some populations can be divided into groups.

Treatments are assigned randomly to the experimental units, or experimental units are randomly assigned among the treatments.

Data collected in the past are used.

An experimenter plans data collection for future studies.

It is a process of collecting information from every unit in the target population.

The questions or measuring devices we use to obtain the data.

Is the reason we refrain from asking leading questions in a poll and always check the zero on the scale before weighing anything in a laboratory.

The population from which the data is collected.

This is sometimes called an independent variable.

The frame is divided into consecutive segments, a random starting point is selected from the first segment, and then a sample is taken from the same point in each segment.

A protocol that describes exactly how the experiment is to be done.

If all treatments are replicated exactly the same number of times in the experiment.

Is a variable whose effect on the response is of interest in the experiment.

Is used to balance the effects of factors you cannot easily control.