Psych Stats, Exam 3

To report the results of the ONE-WAY BETWEEN SUBJECTS ANOVA, which of the following is reported?

-Test statistic -p-value The degrees of freedom (NUMERATOR AND DENOMINATOR)

A researcher conducts a study in which 12 participants are observed at each combination of two factors, where Factor A has three levels and Factor B has two levels. What are the degrees of freedom for the A x B interaction?

3 X 2 ANOVA ??? 4.17

One-Way Between Subjects ANOVA

A statistical procedure used to test hypotheses for ONE FACTOR with TWO OR MORE LEVELS concerning the variance among group means, where different different participants are OBSERVED AT EACH LEVEL OF A FACTOR

The DENOMINATOR of the test statistic for the main effects and interaction in a two-way between-subjects ANOVA

EQUAL TO THE MEAN SQUARE ERROR

A researcher randomly measures social adjustment among children from different family backgrounds (levels of Factor A: divorced, married, single) who engaged in one of five social activities (Factor B). For this study, 10 children were observed in each group. If SSA = 10, MSB = 12, SSAB = 48, and SSW = 405, then which effect was significant at a .05 level using the two-way between-subjects ANOVA? (Hint: If the F-table doesn't include the dfW you're looking for, use dfW = 120.)

FACTOR B ?????

Hypothesis tests used to analyze a significant interaction by comparing the mean differences of ONE FACTOR AT EACH LEVEL OF A SECOND FACTOR is:

SIMPLE main effects

Mean square error (MSE) is another name for mean square within (MSW).

TRUE

Two or more

The one way between subjects ANOV is used when different participants are assigned to ---- group(s)

A researcher computes a 2 × 3 between-subjects ANOVA test in which 11 participants were observed in each condition. If F = 5.17 for both main effect tests and the A × B interaction test, then the decision for each test

WILL BE SIGNIFICANT FOR BOTH MAIN EFFECTS AND THE A x B interaction -----????

What is the critical value for a study with n = 12 in each of two groups at a .05 level of significance?

alpha = .05

A researcher computes a 3 × 4 between-subjects ANOVA. What are the degrees of freedom for Factor A for this study?

dfa = ???? 2

A researcher computes a 3 × 5 between-subjects ANOVA. What are the degrees of freedom for the A × B interaction for this study?

dfab = ???? 8

Which of the following hypotheses identifies a prediction that requires that two factors we observed in the same statistical design?

mood will improve most when people consume foods that are high in sugar and high in fat 2 factors = high fat, high sugar

Homogeneity of variance refers to the assumption that:

the VARIANCE of scores in each population is EQUAL

There are ____ cells or groups in a 3 × 4 ANOVA design.

12 cells or groups

Which post hoc tests is associated with the GREATEST POWER to detect an EFFECT?

Fisher's LSD Test

What are the degrees of freedom numerator for study with n=12 in each of four groups?

n = # of participants per group N = total # of participants in study K = # of groups n/k = df [12/4 = 3]

Not including the total variation, how many sources of variation are measured in a two-way between-subjects ANOVA? (Include all types of between-group variation.)

-factor A -factor a x b -Interaction -Between subjects

A researcher measures attractiveness ratings of a male confederate among 30 women who were told the confederate was either single, dating, or married (n = 10 per group). What are the degrees of freedom for error for the one-way between-subjects ANOVA?

27 N = 30 3 factors (single, dating or married) = K N-K = 30-3 = 27

A researcher compares differences in positivity between participants in a low-, middle-, or upper-middle-class family. If she observes 15 participants in each group, then what are the degrees of freedom for the one-way between-subjects ANOVA?

3 x 2 ANOVA n = 15 participants per group N = 90 K = 6 dfa = k - 1 = 6-1 = 5 dfb = N-K = 90 - 6 = 84 ???????

A researcher conducts two studies. In Study 1, n = 8, p = 2, and q = 2. In Study 2, n = 8, p = 3, and q = 2. If Fobt = 4.06 for the interaction in both studies, then in which study will the decision be to reject the null hypothesis for the interaction test at a .05 level of significance?

???? Study 2

A researcher randomly assigned 16 rodents to experience one of four levels of shock (n = 4 per group) following the illumination of a visual cue. If SSB = 24 and SSW = 48, then what was the decision at a .05 level of significance for a one-way between-subjects ANOVA? (Hint: What is the relationship between SS and MS?)

?????

Using a two-way between-subjects ANOVA, Factor A has two levels, Factor B has two levels, and n = 12 per group. If SSAB = 15 and SSW = 220, then what was the decision for the interaction test at a .05 level of significance? (Hint: You have been given SS, not MS.)

?????? RETAIN the null

A researcher computes two 2 × 2 between-subjects ANOVAs. In Study 1, he observes 8 participants in each cell; in Study 2, he observes 12 participants in each cell. Which study is associated with a larger value for degrees of freedom for the A × B interaction?

Both studies have the same degrees of freedom for the A x B interaction dfab = ???? dfab =

When we arrange the data in an ANOVA test in a table, the number of cells represents the number of ________ in a study.

CELLS = GROUPS

When the variability attributed to BETWEEN GROUPS is EQUAL to the variability attributed to ERROR (within group), then the value of the test statistic for a one-way between-subjects ANOVA is,

EQUAL TO 1

If each main effect is significant, then the interaction must also be significant for a two-way between-subjects ANOVA.

FALSE

A significant ANOVA indicates that ALL pairs of group means significant differ

FALSE (alt. hypothesis is not all means are equal)

A source of variation associated with the variance of group means ACROSS the combination of levels of two factors is called a(n):

INTERACTION

In a two-way between-subjects ANOVA, which effect is potentially the most informative when it is SIGNIFICANT?

INTERACTION

A researcher computes a two-way between-subjects ANOVA and finds a significant A × B interaction and two main effects. Which significant effect should be analyzed first?

Interaction - - has more information when significant

In a study with three groups and 13 participants in each group, the sum of squares for the within-groups source of variation is 18. What is the value for the mean square within-groups in this study

K = 3 n = 13 SS = 18 ????? SSw = 0.5

In a study with four groups and 10 participants in each group, the sum of squares for the between-groups source of variation is 60. What is the value for the mean square between-groups in this study?

K = 4 n = 10 SS = 60 ?? SSb = 20

Without changing the value of ERROR VARIANCE, the ----- between-groups variability, the more likely we are to reject the null hypothesis

LARGER

Using a two-way between-subjects ANOVA with Factor A (Gender: male, female) and Factor B (Type of employment: blue collar, white collar), a researcher found that scores for men and women significantly varied across the levels of the second factor (type of employment). In this study, the researcher found a SIGNIFICANT

MAIN EFFECT OF A x B interaction

Using an A × B ANOVA, a researcher concludes that Factor A is significant, independent of Factor B. In this study, this researcher found a SIGNIFICANT

MAIN EFFECT OF FACTOR A

Which of the following statements is the appropriate way to read the degrees of freedom for an ANOVA with 10 participants in each of four groups?

n = 10 K = 4 N = 40 dfa = k - 1 = 4-1 = 3 dfb = N-K = 40-4 = 36

A researcher conducts a study in which k = 6 and n = 6 per group. What are the critical values for the one-way between-subjects ANOVA at a .05 level of significance?

n = 6 k = 6 N = 36 df = k-1 = 6-1 = 5 df = N-k = 36-6 = 30 (5,30) = ??? 2.53

A researcher assigned participants (n = 8 per group) to read vignettes describing a person engaging in either a helpful, hurtful, or neutral act. Different participants were assigned to each group and asked to rate how positively they viewed the person described in the vignette. What is the critical value for the one-way between-subjects ANOVA at a .05 level of significance?

n = 8 K= 3 N = 24 df = k-1 = 3-1 = 2 df = N-K = 24-3 = 21 (2,21) ???

A researcher randomly assigned 32 children to observe a short clip depicting either their favorite superhero, a parent, a teacher, or no person at all (n = 8 per group). If SSB = 30 and SSW = 104, then what was the decision at a .05 level of significance for a one-way between-subjects ANOVA? (Hint: What is the relationship between SS and MS?)

n = 8 N = 32 K = 4 dfa = K-1 = 32-1 = 31 dfb = N-K = 32-4 = 28 F obt ??? F crit

The TWO-WAY ANOVA differs from the one-way ANOVA in that:

observe the levels of TWO FACTORS

Which measure of PROPORTION OF VARIANCE is the MOST CONSERVATIVE estimate?

omega-squared