FINAL

to increase the chances of rejecting the null, what can we do?

-increase between group variability -decrease within group (error)

What can be done to reject the null

-increase between variability -decrease within group (error)

What type of skewedness does F have?

positively

For a between-subjects, N=

total number of people in the study

A professor compares the exam grades of students based on whether they have a learning disability (yes, no) and where they sit in the classroom (in the front, middle, or back row). Different participants were observed in each group. What type of statistical design is appropriate for this study?

two-way between-subjects ANOVA

How do we recognize when to use 2-way ANOVA?

-1 DV -2 factors or IV

A researcher is interested in determining how quickly (in seconds) subjects respond to a stimulus that varies in size (small, medium, large) and color (dark, bright) What are the factors and state the test of the factorial design

-Factor A: size Factor B: color -test: 3x2 factorial design

What are the rules for power of within-subjects design?

-SSBG increases=power increases -SSE decreases=power increases -MSE decreases=power increases

For a between-subjects ANOVA, what are the 2 most conservative tests?

-Scheffe test -Bonferroni procedure

There are four assumptions to compute the one-way between-subjects ANOVA:

1. Normality--assume that data in the population or populations being sampled from are normally distributed 2. Random Sampling--assume data measured were obtained from a sample that was selected using a random sampling procedure 3. Independence--assume that the probabilities of each measured outcome in a study are independent or equal 4. Homogeneity of Variance--assume that the variance in each population is equal to each other

two-way ANOVA

A statistical procedure used to test hypotheses concerning the variance of groups created by combining the levels of two factors. This test is used when the variance in any one population is unknown.

what is ANOVA?

analysis of variance (o^2)

Sources of variation

any variation that can be measured in a study

normality

assumption that data points are normally distributed such that X and Y scores for two factors form a bivariate normal distribution

linearity

assumption that the best way to describe a pattern of data is using a straight line

homoscedasticity

assumption that there is an equal ("homo") variance or scatter ("scedasticity") of data points dispersed along the regression line

When plotted in a graph, scores are more consistent the ________ they fall to a regression line

closer

the extent to which values of x and y vary independently or separately is placed in the

denominator

perfect occurs when

each data point falls exactly on a straight line

Another name for groups variation

error

the value in the numerator reflects

extent to which values on the x-axis and y-axis vary together

When do you not use a post hoc test?

if the ANOVA is not significant

what's another term for factor?

independent variable

Chapter 13

limitations in interpretation

How do you calculate to get N?

n*k=N

df for correlation are

n-2

Level of factor A symbolized as

p (# of groups)

total # of cells

pq

Level of factor B symbolized as

q (# of groups)

What is within-subjects also called?

repeated measures

Factorial design

research design in which the levels of two or more factors combinded

within-subjects refers to?

same-participants

If a value is closer to 1.0, this indicate what?

stronger correlations

One-way indicats?

testing 1 factor

zero means

there is no linear pattern between two factors

what is a similarity between one and two way ANOVA?

they both have 1 dependent variable

For within-subjects, N=

total number of observations in the study

What do we want to be as large as possible in the F ratio? why?

-MS BG -it represents variance of the treatment/intervention

What are the 2 sources of variation in a one way ANOVA?

-between groups variation -within groups error variation

What are the 3 sources of variation in within-subjects ANOVA?

-between subjects -within subjects -between-persons

When the ANOVA is significant, what do you do? why?

-conduct a post hoc -to determine which pair or pairs of group means significantly differ

What's the difference between a conservative test and a liberal?

-conservative is less power (less likely to reject the null) -liberal has greater power (more likely to reject the null)

What can a correlation be used to do?

-describe the pattern of data points for the values of 2 factors -determine whether the pattern observed in a sample is also present in the pop. from which the sample was selected

what is the column and row?

-dfBG -dfE

The sign of the correlation coefficient indicates only the

-direction -slope of the correlation

A researcher records the amount of time spent studying by male and female college students in a dormitory versus a library setting. The research records 5 students per group. Different participants were observed in each group. Identify each of the following: Factor A, Factor B, p, q, Total # cells, Total # participants:

-gender -study setting -2 -2 -4 -20 (5x2x2)

2 common reasons we observe 2 factors

-hypothesis may require that we observe 2 factors -we need to control for threats to validity (the extent to which we demonstrate the effect we claim to be demonstrating)

2 sources of between groups variation

-main effect for factor A -main effect for factor B -interaction of factors AxB

-Within subjects is associated with _____ power to detect an effect than the _________ -why?

-more -between-subjects -some of the error in the denominator is removed

____ participants are observed ____ times

-n -k

The type of ANOVA you use depends on?

-number of factors -how the participants are observed across each level of a factor

"between-subjects" refers to

-observing different participants 1 time in each group

Power of the one-way within subjects ANOVA is largely based on

-observing the same participants across groups will result in more consistent responding

"within-subjects" refers to

-observing the same participants in each group

What are t tests used to compare for? What about ANOVA?

-one or two means -two or more

Correlation

-statistical procedure used to describe the strength and direction of the linear relationship between 2 factors -weak design

coreelation coefficient (r)

-used to measure the strength and direction of the linear relationship, or correlation between two factors -value of r ranges from -1.0 to 1.0

A researcher compares personality type (extraverts/introverts) on number of math problems in a different environmental setting. Each participant is randomize to complete math problems in a small, crowded room or to a large (uncrowded) room. draw a interpretation of main effects and interactions chapter 12 example 1

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A researcher compares personality type (extraverts/introverts) on number of math problems in a different environmental setting. Each participant is randomize to complete math problems in a small, crowded room or to a large (uncrowded) room. draw a interpretation of main effects and interactions chapter 12 example 2

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A researcher compares personality type (extraverts/introverts) on number of math problems in a different environmental setting. Each participant is randomize to complete math problems in a small, crowded room or to a large (uncrowded) room. draw a interpretation of main effects and interactions chapter 12 example 3

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Chapter 11 practice problem 1

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Chapter 11 practice problem 2

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Chapter 12 practice problem on the back bottom

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How many factors are in One-way ANOVA?

1

How many factors are in two-way ANOVA?

2

Which of the following hypotheses identifies a prediction that requires that two factors be observed in the same statistical design? A. eating slowly will reduce total caloric intake during a meal B. mood will improve most when people consume foods that are high in sugar and fat C. intense exercise will increase cravings for high calorie foods D. the closer a food is to a participant, the more of that food they will consume

A.

Suppose we state the hypothesis the more positive a teacher is with their students, the more students will like their teacher. To test this hypothesis, we would randomly assign a sample of teachers to interact positively or negatively with students in a classroom setting, then have students rate the teachers. One possible threat to validity is the subject may influence ratings. Suppose we tested this hypothesis by using a sample that consisted of sexual health and statistics teachers. Make a table detailing the structure of this study.

Chapter 12 example 3

In ANOVA, we calculate what to serve as the test statistic?

F

Example of a liberal test

Fisher's LSD (least sig. different)

What is the formula for the test statistic?

Fobt=between group variability/within group (error)

Df for within groups

N-k

total # of participants

N=npq

Chapter 11 Part 3: computing a post-hoc test

Steps 1-3

For a between subjects ANOVA, researchers typically use what post-hoc test?

Tukey HSD

A professor compared differences in class grades between students in their freshman, sophomore, junior, and senior years of college. She also compares differences in grades between males and females. If different participants were in each group, then what type of statistical design is appropriate for this study? a) What is the dependent variable? b) What is the factor? c) How many levels or of the factor? d) What design is this ANOVA? e) What is the appropriate name for this type of ANOVA

a.) class grades b.) class and gender c.) 4x2 d.) between subjects e.) two-way between subjects design ANOVA

A researcher records depression scores for 12 patients in each of 4 seasons. If depression scores for the same participants are recorded in each season, then what type of statistical design is most appropriate for this study? a) What is the dependent variable? b) What is the factor? c) How many levels or of the factor? d) What design is this ANOVA? e) What is the appropriate name for this type of ANOVA?

a.) depression b.) seasons c.) 4 d.) within subjects e.) one-way within subjects design ANOVA

A researcher compares differences in health outcomes between participants from a low SES-, middle, or high SES background. Each participant completes an online survey about socioeconomic status and health outcomes. a) What is the dependent variable? b) factor? c) How many levels or of the factor? d) What design is this ANOVA? e) What is the appropriate name for this type of ANOVA

a.) health outcomes b.) socioeconomic factor c.) 3 d.) between subjects e.) one-way between subjects design ANOVA

A researcher is interested in studying if Alcoholics Anonymous and individual counseling combined is the most effective treatment for lowering alcohol consumption. Study participants into three levels: medication only, medication and counseling, and counseling only. The researcher records the number of alcoholic beverages consumed in the past 2 weeks following treatment. Compute a one-way between subjects ANOVA with an α = .05. Conduct an ANOVA to analyze significance of data at a .05 level of significance (look at chart)

chapter 11 Part VI question 1

Df for between

k-1

A researcher compares differences in health outcomes between participants from a low SES-, middle, or high SES background. She collects 20 participants from each SES background. Each participant completes an online survey about socioeconomic status and health outcomes. Identify all of the following: k= n= N=

k=3 n=20 N=60

A researcher records depression scores for 12 patients in each of 4 seasons. If depression scores for the same participants are recorded in each season, then what type of statistical design is most appropriate for this study k= n= N=

k=4 n=12 N=48

For behavior research, we mostly describe the ________ relationship between two factors

linear

coefficient of determination (r^2 or R^2)

mathematically equivalent to eta-squared, and is used to measure the proportion of variance of one factor that can be explained by known values of a second factor

k

number of groups

n

number of participants per group

N

number of total participants in a study

How are correlations typically illustrated through?

scatterplots

correlation coefficient r is

test statistic for the hypothesis test

the term "one-way" refers to

testing 1 factor

regression line

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

Pearson (product moment) correlation

used to measure the direction and strength of the linear relationship of two factors in which the data for both factors are measured on an interval or ratio scale of measurement