Chapter 11 The t Test for Two Related Samples

What are the 4-step process used for hypothesis test w/the repeated-measures t statistic?

1- State the hypotheses, and select the alpha level. 2-Locate the critical region. 3-Calculate the t statistic. 4-Make a decision (keep/reject the null hypothesis).

State the 3-step process in order to find the t-statistic.

1-Compute the sample variance. 2-Use the sample variance to compute the estimated standard error. 3-Use the sample mean (MsubD) minus the hypothesized population mean (usubD) / the estimated standard error to compute the value for the t-statistic.

What does a matched-subjects design involve?

A matched-subjects design involves two separate samples, but each individual in one sample is matched one-to-one with an individual in the other sample.

When dealing with relatively few subjects, rare species/individuals in rare professions, what measure should be chosen?

A repeated-measures design.

Variance and sample size influence, hypothesis test, but variance has a large influence on what measures of effect size?

Cohen's d and r^2

What is the difference score for repeated measures study?

D= Xsub2 - Xsub1

State the formula for SS (ED^2)

ED^2- (ED)^2/n

True/False. In repeated-measures t Test, Variability of the scores and the size of the sample both do not influence of the magnitude of the estimated standard error in the denominator of the t statistics.

False Variability of the scores and the size of the sample both do influence of the magnitude of the estimated standard error in the denominator of the t statistics.

True/False. Larger variance produces a larger values for the t statistic (closer to zero) and reduces the likelihood of finding a significant result.

False. Larger variance produces a smaller values for the t statistic (closer to zero) and reduces the likelihood of finding a significant result.

What are individual difference? Which measure design is the primary advantage to use for individual differences?

Individual differences are characteristics such as age, IQ, gender, and personality that vary from one individual to another. The repeated-measures design.

How does one measure the absolute magnitude of the effect size for the repeated-measures t?

Most commonly used measures of effect size are Cohen's d, r^2 and also confidence interval to estimate the population of mean difference.

What is the formula for mean for sample of scores in repeated measures study?

MsubD= Difference D/n

What is repeated-measures design/ within-subject design?

One in which the dependent variable is measured two or more times for each individual in a single sample.

Sate the formula for cohen's d

Sample mean difference/[square] sample mean deviation ( MsubD/s)

Sample size has no effect on the value of Cohen's d and only a _____ influence on r^2

Sample size has no effect on the value of Cohen's d and only a small influence on r^2

What is the formula for estimated standard error for the repeated-measures design?

SsubMsubD= [square] s^2/n or s/[square]n

In matched-subjects design, why are each individuals in one sample matched with an individual in the other sample?

The matching is done so that the two individuals are equivalent (or nearly equivalent) with respect to a specific variable that the researcher would like to control.

True/False A larger mean difference increases the likelihood of rejecting the null hypothesis and increases measures of effect size.

True

True/False A repeated-measures design typically requires fewer subjects than an independent-measures design.

True

True/False The size of the sample mean difference changes the effect size.

True

True/False is it customary to ignore the minus sign and report Cohen's d as a positive value when measuring the size of the effect and not the direction?

True

True/False is the same group of subjects used in all ot the treatment conditions when using repeated-measures design/within-subject design?

True

True/False. A larger sample produces a larger value for the t statistic (farther from zero) and increases the likelihood of rejecting Hsub0.

True.

Formula for confidence interval (used as an alternative method for in measuring size and effect of treatment).

UsubD=MsubD +- tssubMsubD

State the formula: S^2 = SS/n-1 | s

Variance/standard deviation

Sample statistic - population i parameter/Estimated standard error. State the formula.

What is t-score?

State the formula for percentage of variance accounted for, r^2

r^2= t^2/t^2 + df

What measure design is best suited for studying learning, development, or other changes that take place over time?

the repeated-measures design.