Psychology Exam 5: Intro to Analysis of Variance

In an ANOVA, how is the df total calculated

(# of participants in each group * times the number of groups)-1

On average, what value is expected for the F-ratio if the null hypothesis is true?

1.00

Mean Square (MS)

In analysis of variance, a sample variance is called a mean square, indicating that variance measures the mean of the squared deviations.

In an ANOVA, what is represented by the letter N

The number of scores in the total research study

In an ANOVA, what is represented by the letter T?

The sum of the scores in a specific treatment

For an ANOVA comparing three treatment conditions what is stated by the null hypothesis? (Ho)

There are no differences between any of the population means u1=u2=u3

In analysis of variance, what is measured by the MS values?

sample variance

between-treatments variance

values used to measure and describe the differences between treatments (mean differences)

In an ANOVA, how is the df (between treatments) calculated?

(# of treatment groups)-1

In an analysis of variance, differences between participants contribute to which of the following variances?

Both between-treatments variance and within-treatments variance.

error term

For ANOVA, the denominator of the F-ratio is called the error term. The error term provides a measure of the variance caused by random unsystematic differences. When the treatment effect is 0 (H0 is true), the error term measures the same sources of variance as the numerator of the F-ratio, so the value of the F-ratio is expected to be nearly equal to 1.00

Level

In an experiment, the different values of the independent variable selected to create and define the treatment conditions. in other research studies, the different values of a factor.

T/F Post tests such as Scheffé are not necessary for an analysis of variance comparing only 2 treatment conditions?

True

When comparing more than 2 treatment means, why should you use an analysis of variance instead of using several t tests?

Using several t tests increases the risk of a Type I error

What is ANOVA (analysis of variance)

a hypothesis-testing procedure that is used to evaluate mean differences between 2 or more treatments (or populations)

What does ANOVA stand for?

analysis of variance

Factor

in analysis of variance, an independent variable (or quasi-independent variable) is called a factor

testwise alpha level

systematic differences that are caused by changing treatment conditions

within-treaments variance

the difference that exist inside each treatment condition

experimentwise alpha level

the risk of a type I error that accumulates as you do more and more separate tests

F-ratio

the test statistic for analysis of variance is called an F-ratio and compares the differences (variance) between treatments with the differences (variance) that are expected by chance