Exam 10: Testing Means: Related Samples T Test

A researcher placed male rodents in the presence and absence of a conspecific male.Cortisol (a stress hormone)levels were compared at both times.What type of t test is most appropriate for this study?

Both estimates of proportion of variance, and ,are computed the same for independent and related samples t tests.

A study in which 26 participants are observed two times is associated with 26 degrees of freedom for a related samples t test.

The test statistic for a related samples t test makes tests concerning a single sample of

The estimated Cohen's d for the related samples t test uses the sample standard deviation for difference scores as an estimate of the standard deviation of difference scores in the population.

For the related samples t test,assuming that all other values remain constant,then as samples size increases,

A researcher computes the mean difference in locomotion in a sample of 12 rats before and 30 minutes after an injection of amphetamine.Rats were placed in a box with infrared beams.The number of times rats crossed the beams was used as a measure of locomotion.The mean difference in locomotion was 6.2±8.4 ( ),and this difference was significant.What is the effect size for this result using estimated Cohen's d?

A researcher conditions rats to fear a tone that was sounded just prior to a brief shock.To measure fear following this conditioning,she records the number of lever presses by each rat in the presence and in the absence of the tone.It was hypothesized that reduced lever pressing in the presence of the tone was evidence for a conditioned fear response in rats.If the researcher tested this hypothesis at a .05 level of significance (two-tailed test),then what is her decision if she computes t = ñ2.842 in a sample of 8 rats.

A researcher sampled 25 participants and measured their alcohol consumption (in ounces)in both a home and a bar setting.If the mean difference in satisfaction ratings for this sample was 11.4±2.5 ( ),then what is the decision at a .05 level of significance?

Each of the following is an advantage for using the related samples design,except

Selecting related samples increases standard error and reduces power.

Selecting related samples minimizes standard error and increases power.

A professor compares scores on a competency exam among students at two times during a single semester.What type of t test is most appropriate for this study?

To increase the value of estimated Cohen's d,a researcher increases the sample size.Will this change the value of d?

A professor computes the mean difference in exam scores before and after a lecture as 9.0±14.5 ( ),and this difference was significant.What is the effect size for this result using estimated Cohen's d?

How does the test statistic differ for a t test using the repeated measures versus the matched samples design?

The related samples design can ________.

The related samples t test is associated with no degrees of freedom.

The related samples design can ________ the power to detect an effect by making the standard error ________.

When reporting data in a results section,it is ____ necessary to identify the type of t test computed.