Exam 8: Introduction to the T Test: Single Sample and Dependent Means

The t test is sometimes called __________ because its main principles were developed by William Gosset who published his articles anonymously using the name "__________."

The more degrees of freedom, the closer a t distribution is to the __________.

From the statement "t(32)= 2.80, p < .01," the number of people in the sample is assumed to be __________.

When results of t tests are presented in a table, __________ will often be used to indicate level of significance.

Other names for the t test for dependent means include all of the following EXCEPT:

What is the approximate power for a study using the t test for dependent means with an expected large effect size, one-tailed and N = 50?

In a single-sample t test, suppose the mean of your sample is 95, the mean of Population 2 is 75, and the standard deviation of the distribution of means is 5. What is the t score?

What type of research design would be expected to yield the highest amount of power (assuming studies with the same sample size)?

A local newspaper reports that young women in your town (i.e., a known population)sleep an average of only 5 hours per night. However, you think that women in your town who are enrolled at your college sleep more than that. You randomly select 200 women from your college and ask them to accurately record their hours of sleep. You find that they sleep an average of 7 hours per night. What test would you use to determine whether this mean difference is statistically meaningful?

The formula, (M-Population M)/SM, gives you the __________.

If not otherwise indicated, one should assume that researchers utilized a __________ test.

There are specially constructed tables that provide the approximate number of participants needed to achieve __________ power for a planned study involving a t test.

A researcher working at a particular company wants to know if workers' health would improve if they were given extra days 'off. In this company, all workers undergo a standard physical exam twice a year and after each exam an overall health rating (higher scores mean better health)is automatically provided to the company. To conduct the study, the researcher selected five workers at random. She then arranged to have these five workers receive an additional 2 days off every month over the period between health exams. She then compared the health scores on the two exams. Do the results shown in the table below support the notion that extra days off improves health? (Use the .05 level.) a. Use the five steps of hypothesis testing b. Figure the effect size and find the approximate power of this study. c. Explain your results. Health Rating, Before and After Period of Extra Days Off Worker Before After A 75 81 B 66 67 C 44 46 D 86 88 E 89 89

For the following question(s): A research article included the following table: Mean Score on Four Questionnaire Scales Before and After the Experimental Manipulation Questionnaire Before After Change Dominance 18.42 16.31 -2.11 Independence 17.25 21.38 4.13** Conformity 18.97 17.20-1.77* Nurturance 16.11 13.89 -2.22* ______________________ *p < .05; **p < .01 -Which of the following differences was NOT statistically significant?

A circumstance that creates a serious problem (in terms of meeting assumptions)when using the t test for dependent means is when the population is highly __________ and you are conducting a one-tailed test.

Gosset discovered the t distribution while attempting to:

One can carry out a t test for dependent means in much the same way as a t test for a single, except for the use of __________.

Suppose a researcher conducted a t test for dependent means using scores from pairs of research participants (i.e., mothers and sons). The researcher considered each pair as if it were one person and calculated a difference score for each pair. In this example, the t test could also be called a:

Testing participants before and after an experimental manipulation is called a(n)_________ design.

When the results of a t test are presented in research articles, the __________ directly follow(s)the "t" and are in parentheses.