How to improve the internal validity of an experiment 35

Answer]: Internal validity. (1) Meaning:

Internal validity refers to the degree to which the causal relationship between the independent variable and the dependent variable in an experiment is clear. If the independent variable and not other factors caused the change in the dependent variable, then the experiment had high internal validity. So the internal validity is related to the control of additional variables.

2) Influencing factors: the interaction between the subjects of the main test and the subject, including the required characteristics and the experimenter effect. The effects can be controlled with a double-blind experiment.

Statistical regression regression to the mean of the normal distribution. It has a great impact on the subjects with extreme special lesions, and some inherent and learned differences of the subjects can be controlled by matching method and analysis of covariance, such as gender, age, experience, personality, etc., which have a certain impact on the research. If, in an experimental study, there is significant confusion due to the above reasons, resulting in a change in the longitudinal and vertical of the independent variable that does not cause a corresponding change in the dependent variable, then the experiment will have zero results.

Therefore, if a zero result does not really mean that the independent variable is not related to the dependent variable, then it must indicate that there is a big problem with the internal validity of the experiment.

Validity: The extent to which an experimental method achieves the purpose of the experiment.

Internal validity, part of which is extracted as statistical conclusion validity. External validity proposes a part named Ideation Validity.

What it means: Refers to an independent variable in a study.

Causal relationship with the dependent variable.

degree of certainty.

Influencing factors: History; Choose; The subject died. Ripe; growth in quiz experience; Fatigue factor (Hawthorne effect.

placebo effect, requirements characteristic dust ants). Precision and reliability of experimenters and measurement methods, statistical regression factors. The interaction between choice and maturity.

Improvement method: Perform a rigorous experimental design – independent, dependent, and extraneous variables.

control. Strictly monitor the experimental implementation plan, process (accidents) and links.

Meaning: refers to the degree to which the research results can be generalized and generalized in other similar contexts, that is, the general representativeness and applicability of the research results.

Influencing factors: the reaction effect of the test; the reaction effect of the experimental arrangement; Interference from repeated experimental treatments. Interaction of selection bias with experimental variables.

Improvement method: increase the representativeness of the sample, overcome the excessive artificial contextualization of the experiment, and ensure the validity of the measurement tool.

The statistical regression effect, in which students who performed poorly on the first test may perform better on the second test, while students who performed better on the first test may do the opposite, is called the statistical regression effect.

What it means: The accuracy of the conception of the relationship between the variables and the degree to which the experimental variables are defined in the operation of the experiment and the inferences are defined.

Influencing Factors: Idea: Incomplete analysis of the idea prior to operation. Confusing ideation and ideation hierarchies. There is limited promotion between ideas and ideas.

Subjects and Participants: Characteristics are required. The participant's sense of insecurity about the evaluation of Zaichun. Experimenter expectation effect.

Procedures and Operations: Deviations from a single operation; Deviation from a single approach.

Interactions: Interactions of different treatments; Interaction between testing and experimental processing.

Meaning: The degree of validity of statistical conclusions caused by the appropriateness of statistical methods, which mainly reflects the relationship between statistics and population parameters.

Influencing Factors: Statistical Methods: Low statistical verification power (sample size, significance level.

a size, error variation size). The degree to which the assumptions on which the selected statistical method is based are satisfied. Multiple comparisons and error variations.

Participant: Random variation of the participant.

Tools: Measure the reliability of the tool.

Procedure: The reliability of the experimental treatment execution, i.e., the degree to which the design requirements were adhered to when the experiment was performed.

Internal validity refers to the certainty of the cause of the change in the dependent variable.

For example, a person's sensitivity to light (dependent variable) is not due to a change in light intensity (independent variable).

External validity refers to the degree to which we can generalize after we have done an experiment.

For example, the subjects we do in some key schools do not necessarily represent the level of all students (there is a difference between key schools and ordinary schools).

So in this case, the generalizability is relatively low.

Reliability refers to the degree of agreement across multiple measurements.

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Answer]: b, c, d

Internal validity refers to the degree to which an experimental variable can be accurately estimated. If the additional variables in the experimental envy are not adequately controlled, then the effects of these additional factors may be confused with the independent variables, and the conclusion of causality is not completely certain. If the independent or dependent variable is not clearly defined, a clear causal conclusion cannot be obtained.

Answer]: C can be calculated according to the formula of ch d, d = (160-125) 30 =.