# Flashcard Set Preview

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What are the requirements for an experiment to be internally valid?

All variables/conditions are held constant except for the manipulation
of the independent...

What are the implications when an experiment is internally valid?

The researcher is likely to be able to claim that the independent variable caused the observed...

When does an experiment involve a confounding?

When the independent variable of interest and a potential independent variable are allowed...

What does it mean to hold conditions constant in an experiment? What is the purpose of...

That all materials, instructions, and experiences within the experiment are identical across...

How and why do researchers balance participants’ individual differences across conditions...

Through random assignment, which works by generating groups of participants that are equivalent...

What is the logic behind establishing the independent variable as the cause of a change in...

Beginning with comparable groups, treating them differently and ending with non-comparable...

What are intact groups, and why do they pose the potential problem of confounding?

Groups that exist prior to the experiment, without the researcher randomly assigning participants...

What is subject loss and why does it threaten the internal validity of the experiment?

When participants do not complete the experiment – mechanical or selective. Mechanical is...

Which type of subject loss poses the most serious threat to internal validity?

The loss is selective in that some characteristic of the participant that is related to the...

What are two procedures typically used to control for demand characteristics and experimenter...

Placebo control groups and double-blind procedures.

What is effect size?

A measure of the strength of the relationship between the independent and dependent variables...

What is a meta-analysis?

The statistical tool that is used to analyze the results of several independent experiments.

What is the null hypothesis? How does null hypothesis testing work and what is the purpose?

That there is no relationship between the IV and DV.To determine whether the IV has a reliable...

What does it mean to say that the outcome of an experiment is statistically significant?

That the outcome has a small likelihood of occurring if the null hypothesis is true (i.e.,...

What are Type I and Type II error?

Type I error = false positive; α or p. A Type I error occurs when the null hypothesis is really...

What is a matched groups design? What is the preferred pretest (matching) task for a...

When only a small sample is available, the researcher can match the participants on some variable...

What is a natural groups design?

To differentiate experiments involving individual differences (subject) variables and those...

What is the most critical problem in drawing causal inferences based on a natural groups design?

Eliminating plausible alternative causes for the obtained relationship.

What are the reasons researchers choose to use repeated measures designs?

Require fewer subjects More convenient and efficient Needed when the experimental procedures...

What is counterbalancing and what is its purpose?

Averaging practice effects across conditions of a repeated measures design.

The need to balance practice effects in the repeated measures design is analogous to what in...

The need to balance individual differences.

What does the complete repeated measures design entail?

When each participant completes each condition of the experiment multiple times, so practice...

What is the additional step needed when analyzing the results in a complete repeated design?

To average each participant’s scores for each condition.

What does the incomplete repeated measures design entail?

Each participant completes each condition of the experiment only once, but practice effects...

What is block randomization in the context of balancing practice effects across experimental...

Generate a new random order for each time the participant completes the conditions of the experiment...

What is the ABBA counterbalancing technique? When should it be used versus not be used?

Present one random sequence of conditions (e.g., DABC), then present the opposite of the sequence...

What are anticipation effects?

When participants develop expectations about which condition will appear next in a sequence.

What is the general rule that applies to each of the three techniques that are used to balance...

Each condition (e.g., A, B, C) must appear in each ordinal position (1st, 2nd, 3rd) equally...

What is the Latin Square technique for selecting orders in the incomplete repeated measures...

Each condition precedes and follows each other condition exactly once with the Latin Square...

Why are repeated measures designs more sensitive at detecting the effects of independent variables...

Because the systematic variation caused by individual differences is eliminated from the statistical...

What is differential transfer?

When the effects of the manipulation for a condition persist or carryover into the subsequent...

What information does the estimated standard error of the mean provide?

Information about how well the sample mean estimates the population mean.

How is a confidence interval similar to a margin of error?

They are essentially the same thing.

How is a 95% confidence interval for a population mean calculated?

Sample mean ± (t critical) (estimated standard error)

Having calculated a 95% confidence interval for a single population mean, what can we claim?...

That the odds are 95/100 that the obtained interval contains the population mean. ...

What do we do differently to construct a confidence interval for a comparison between two independent...

We substitute the difference between two sample means for a single sample mean. ...

When interpreting confidence intervals, what does it mean when the intervals overlap?

We cannot be certain about the true population mean difference.

What about when the intervals do not overlap?

We have evidence that the population means differ.

What is the null hypothesis? (Hint: What assumption does the null hypothesis make?)

That the independent variable did not have an effect.

Null hypothesis significance testing uses the laws of probability to estimate the likelihood...

The likelihood of an outcome assuming that only chance factors caused the outcome.

What does it mean to say that a result or effect is statistically significant? What does...

Statistically significant: The IV had an effect on the DV, and there is less than a 5%...

How are Type I error, p-value, and level of significance related?

Know how to apply these concepts to an example. The stated p-value is the level of significance,...

What factors are related to the power of a statistical test comparing two means?

Sample size Level of significance Effect size

What is the primary factor that researchers use to control the power of a statistical test?

Sample size

When is the t-test for independent groups the appropriate inferential test?

When comparing two independent means.

When is the repeated measures t-test the appropriate inferential test?

When each subject participates in both conditions of an experiment.

Why might “statistically significant” results not be of interest to the scientific community?

The study's methodology was poor. The results have little external validity. The treatment...

The probability we use to define a statistically significant outcome is called the/is the same...

p-value, alpha, type I error, level of significance

What is the most common error associated with null hypothesis testing in psychological research?...

Type II error (NOT Type I error, which we keep below .05/5%. We are willing to...

How should and shouldn’t you report a "statistically significant" finding? ...

Should: As supporting the researcher's hypothesis.Shouldn’t: As proving the researcher's...

What are confidence intervals? How are they used to determine whether the population...

A range in which we are (usually 95%) confident the true population mean lies.We can be confident...

What does it mean to say that an experiment’s findings are reliable?

When the results of an experiment are likely to be replicated if the procedures are repeated,...

What is involved in a partial replication of an experiment? What is the purpose of a...

Replicating the study with minor changes to the sample, materials, procedure. Purpose is to...