Stats quiz 3

df discipline

# levels - 1

df discipline x situation

(#levels -1) (#levels - 1)

SS regression

(predicted value of y - mean of y)2

what percent fo variation in Y can be expalined by X

(predicted value of y - mean of y)^2/(y - mean of y)^2

correlation coefficient

(r) -1.0 to +1.0 perfect means straight line the stronger the correlation the more likely the two factors are related

df total

(total observations - 1)

df error

(total observations) - (#levels of ____)(#levels of situation)

SS residual (error)

(y - predicted value of y)2

what percent of variation in Y cannot be explained by X

(y - predicted value of y)^2/(predicted value of y - mean of y)^2

equation of the regression line

Y = bX+a slope b = change in y/change in X

Simple main effect tests are necessary to analyze ______.

a significant interaction

when two lines are parallel

a significant interaction is not likely

an outlier

can change direction and strength of a correlaiotn

Y

crierion variable

computing the two way between subjects ANOVA

df Factor a: p-1 df Factor B: q - 1 df for AxB interaction: (p-1)(q-1) dfE = pq(n-1) dfTotal = npq-1 test statistic:

covariance

the extent to which two factors vary together

A researcher conducts a study using the one-way between-subjects ANOVA. She computes SSBG= 180 and SST= 520. What is the effect size for this test using eta squared?

.35

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 interaction?

2

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

3

A researcher reports that alertness in the classroom varies by the intensity of lighting in the room, F(3, 36) = 3.96, p < .05. How many light intensity groups were observed in this study?

4

A researcher conducts a study in which six participants are observed at each combination of two factors, where Factor A has two levels and Factor B has three levels. What is the critical value for the main effect test of Factor A using a .05 level of significance?

4.17 (1, 30) dfA and dfE

1. Parents learn tricks that are helpful in raising children and in preserving the sanity of all concerned. When a baby is crying, just changing diapers will stop crying 25 percent of the time. Picking the baby up and walking stops crying 40 percent of the time. Suppose a (desperate?) parent did both. Which outcome (percent) would indicate that the effect of the two tricks is independent, that they do not interact.

65

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

groups

Six hypothetical results for two factors (A and B)

?? p 345

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 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

assumptions of tests for linear correlations

homocedasticity linearity normality

Which post hoc test is associated with the greatest power to detect an effect?

Fisher's LSD test

Analysis of regression

H0: The variance of Y is not related to the variance of X H1: The variance of Y is related to the variance of X test statistic: df for regression variation: # of predictor variables (1) df for residual variation: sample size n - 2 SSregression = r^2SSy where r = SSxy/√(SSxSSy) SSresidual = (1-r^2)SSy SSy = SSregression + SSresidual Fobt = MS regression/ MS residual or (SS regression/1)/(SSresidual/(n-2)) compare to critical value: use df of numerator (1) and df of denominator (n-2)

method of least squares steps

Mx and My SSxy or SP (sum of products of x and y Σ(X-Mx)(Y-My)) SSx (Σ(X-M^2)) sum of squares for x. b = SSxy/SSx a = My-bMx ˆY = bX + a

A researcher conducts two studies. In Study 1, the main effect of Factor A was significant. In Study 2, the main effect of Factor A was not significant. If the value of eta squared for Factor A was the same in both studies, then in which study was the effect size the largest?

Selected the value is the same in both studies

regression line creates smallest possible value of

Sum of Squares???

regression line

best=fitting straight line to a set of data points. minimizes the distance of all data points that fall from it.

Which of the following is a source of variation in the one-way within-subjects ANOVA but not in the one-way between-subjects ANOVA?

between-persons variation

ss interaction =

ss cells - ss a - ss b

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

interaction?

The pearson correlation coefficient

measures direction and strength of linear relationship of two factors.

does correlation show cause

no

ssumption of the two-way between-subjects ANOVA?

normality random sampling homogeneity of variance

computing 2 way between subjects anova

normality random sampling independence homogeneity of variance

• Since this is a "within-subjects" design, which of these do you expect to be different from the preceding study?

o SSERROR Different o SSBG Same o SSTOTAL Same o F-ratio Different o Tukey's HSD Different o Effect size Different

Which measure of proportion of variance is the most conservative estimate?

omega squared

A statistical procedure used to test hypotheses for one factor with two or more levels concerning the variance among group means, where different participants are observed at each level of a factor, is called the ______.

one-way between-subjects ANOVA

when two lines touch or cross

possible significant interaction

X

predictor variable

Restriction of range

range of data is limited- sample is not the populatoin

lines crossing often indicate

siginificant interaction

analysis of regression

similar to Anova...

Hypothesis tests used to analyze a significant interaction by comparing the mean differences of one factor at each level of a second factor are called ______.

simple main effect tests

A researcher conducts two studies on memory. In Study 1, eight participants observed each of three visual clips and recorded how many items from each clip they could recall. Study 2 was again n = 8, but participants viewed each of four video clips in this study. If dfE= 32 and SSE= 110 in both studies, then in which study is the value of mean square error the largest?

study 1????

To report the results of the two-way between-subjects ANOVA and post hoc tests, which of the following is reported?

the test statistic for each significant main effect and interaction the p value for each significant main effect and interaction the post hoc tests used to analyze significant main effects

method of least squares

to find regression line??

residual variation

variance in Y not related to changes in X

regression variation

variance in Y related to changes in x

The source of variation that cannot be attributed to or caused by having different groups is called ______.

within-groups variation error variation

standard error of the estimate

√(MS residual) shows spread among residual values