experimental psych unit 3 questions from quizzes

A multivariate analysis of variance is used to evaluate experiments with

multiple dependent variables.

Until we can determine otherwise, we assume that the

null hypothesis is true

Karen performed a large N experiment and based her conclusions on group averages. Which aggregation technique did she use?

aggregation over stimuli

Researchers pool data and base their conclusions on group averages in

aggregation over subjects.

The ____ divides a distribution of scores in half.

median

When your distribution of scores is 1 2 4 9 10 10, you should use the _____ to represent central tendency.

median

Theoretically, if an independent variable has no effect in an experiment, the F ratio should be

1

There are three levels of factor A and two levels of factor B in a two-way ANOVA. How many degrees of freedom will there be in the numerator of an F test for factor A?

2

How many F ratios must we calculate for a two-way analysis of variance?

3

If Renee has 60 subjects and 2 degrees of freedom between groups in a one-way analysis of variance, her independent variable must have ___ levels.

3

If Zack has 75 subjects and 72 degrees of freedom within groups in a one-way analysis of variance, his independent variable must have ___ levels.

3

Which of these represent(s) the proportion of variance shared by two variables?

? 2 and r 2

____ describes the consistency of an effect across past studies and estimates average effect sizes.

meta analysis

How do a priori tests differ from post hoc tests?

A priori tests can be performed instead of an F test, while post hoc tests cannot be performed without a significant F test.

All of these illustrate a directional hypothesis except:

The risk of heart attack differs for patients who exercise or who are sedentary.

___ verifies how successfully the experimenter created values of the independent variable.

a manipulation check

An experiment 's validity is threatened by ____ when subjects do not reveal all they know about the purpose of an experiment and researchers accept subject reports at face value.

a pact of ignorance

Dr. Moss privately worries that his subjects may have guessed his research hypothesis, but doesn't press his subjects for information. Several of his subjects believe that they know the experiment's purpose, but do not reveal this to Dr. Moss. What problem does this situation describe?

a pact of ignorance

If Mark chose a .01 significance level for his experiment and then found that the results could have occurred by chance more than 1 out of 100 times, he should

accept the null hypothesis.

Jeffrey administers a depression inventory and social activity journal to offset the errors that could result from using a single incomplete assessment instrument. This strategy is called

aggregation over measures.

The primary advantage of multivariate designs is that they

allow us to study combinations of dependent variables that better represent reality.

When a researcher rejects the null hypothesis, this means that the experimental results

are statistically significant

You should decide which test of significance to use

as you plan the design of your study.

If Jennifer's results come close to reaching statistical significance, she should

be cautious in drawing any conclusions

Statisticians use ____ to represent the probability of committing a Type 2 error.

beta

A chi square test

compares the frequencies of responses in our sample with those expected in the population.

Jack just completed a study of the effects of caffeine and rave music on recall. He is excited about finding a significant interaction and says, "This is so cool! I've proved my research hypothesis. Jolt cola with rave music is the way to study." Jack's experiment cannot prove his research hypothesis because his results could be due to

confounding and/or Type 1 error.

Cramer's coefficient Phi ( ?) estimates the ?

degree of association between two categorical variables.

Orne's (1969) "pact of ignorance" shows how validity issues can be hard to resolve because of

demand characteristics

Experiments by Ritchey and Armstrong (1982) showed that subjects recalled ____ when the degree of ____ was controlled.

detailed drawings better than less elaborate drawings; distinctiveness

When independent variables produce stronger effects on some dependent variables than others, this represents a(n)

difference in trends

The analysis of variance

divides variability in the data into component parts and then compares and evaluates them for statistical significance.

The principal advantage of a two-way analysis of variance over a one-way analysis of variance is that a two-way analysis of variance

evaluates interaction effects

Compared with a t test for independent groups, a t test for matched groups almost always

has a lower chance of Type 2 error and is more powerful.

Chapter 15...The advantage of unobtrusive measures is that they

have greater external validity and yield more realistic data.

Which reasoning process do researchers require to extend experimental findings to broader principles and implications?

induction

Many researchers attempt to discover whether subjects understood and followed experimental instructions by

informally interviewing subjects at the end of an experiment.

Puck presented subjects with three different sets of student pictures and asked them to recall as many names as possible from each set. One set contained pictures of cheerleaders. A second featured pictures of glee club members. The final set consisted of pictures of ultimate Frisbee players. Which statistical test should Puck use to analyze his data?

one-way repeated measures analysis of variance

A researcher discovered that antibiotic therapy is more effective in treating chronic ulcer than conventional medication. Since he knows this finding challenges conventional wisdom, he decides to use a strict evaluation criterion. The risk of committing a Type 1 error will be lowest if he chooses

p<.01

When we set our significance level at .01, this corresponds to the notation

p<.01

chapter 14... Which scale allows us to conclude that the group trained to breathe diaphragmatically experienced half the panic attacks as the control group?

ratio

Rachel's computed value of F was 7.23 and the table value of F was 3.88 at the .05 level. She should ____ the null hypothesis and conclude that her results were

reject; statistically significant

Dr. M. predicted that heart rate variability biofeedback would reduce depressive symptoms. She randomly assigned depressed patients to either receive 2 hours of heart rate variability training or 2 hours of yoga instruction and measured changes in Beck Depression Inventory scores. Since the heart rate variability group improved more than the yoga group, she

rejected Ho

Sample size affects

test statistic size and variability

Psychological Science has replaced p values with

the average probability of replication

We reject the null hypothesis when.

the computed value of t is more extreme than the critical value of t.

The results of an experiment are statistically significant when

the difference between group scores exceeds normal variability

All of these factors affect the degree to which we can generalize from the results of an experiment except

the significance level we choose to evaluate our findings

Donovan conducted an experiment to test the hypothesis that subjects learn words with positive connotations more quickly than words with negative connotations. Although the experimental manipulation produced a real effect, there was so much variability among subject responses that Donovan decided he could not reject the null hypothesis. Donovan's decision illustrates

type 2 error

Low statistical power reduces statistical conclusion validity and can produce

type 2 errors

Students surveyed about the number of MP3s they download each week report widely diverse numbers. This pattern of results illustrates what we mean by

variability

The altitude of Mt. Whitney is 4418 meters, while the altitude of Death Valley is 86 meters below sea level. The difference in their altitudes illustrates the concept of

variability

When we perform a statistical test, we evaluate

whether the null hypothesis is a likely explanation for our results.