Exam 9: The T Test for Independent Groups Samples

t(14) = 3.35, one-tailed. Based on these results, we _____.

Imagine that you conducted an independent-groups t test with 7 subjects in each group. For a two-tailed test, the t_cv at $\alpha$ = .05 would be:

The null hypothesis for a one-tailed independent-groups t test states that:

In the formula for an independent-groups t test, the denominator in the equation represents:

t(20) = 1.99, two-tailed. Based on these results, we _____.

A college student is interested in whether there is a difference between male and female students in the amount of time spent working out each week. The student gathers information from a random sample of male and female students on campus. The amount of time spent working out is normally distributed. The data are given below. -Should H₀ be rejected? What should the researcher conclude?

The alternative hypothesis for a one-tailed independent-groups t test states that:

A student is interested in whether students who study with others devote as much attention to their studies as do students who study alone. He believes those who study alone devote more attention to their studies. He randomly assigns subjects to either group or individual study conditions and has them read and study the same passage of information for the same amount of time. Subjects are then all given the same 10-item test on the material. Their scores appear below. Scores on the test represent interval/ratio data and are normally distributed. -What statistical test should be used to analyze these data?

If an independent-groups t test has 13 subjects in each group, then the degrees of freedom are:

A college student is interested in whether there is a difference between male and female students in the amount of time spent working out each week. The student gathers information from a random sample of male and female students on campus. The amount of time spent working out is normally distributed. The data are given below. -If significant, draw a graph representing the data.

A student is interested in whether students who study with others devote as much attention to their studies as do students who study alone. He believes those who study alone devote more attention to their studies. He randomly assigns subjects to either group or individual study conditions and has them read and study the same passage of information for the same amount of time. Subjects are then all given the same 10-item test on the material. Their scores appear below. Scores on the test represent interval/ratio data and are normally distributed. -Identify H₀ and Ha for this study.

If the null hypothesis is not supported, then the t test should be:

If a researcher reported for an independent-groups t test that t(12) = 3.66, p < .01, how many subjects were there in the study?

A college student is interested in whether there is a difference between male and female students in the amount of time spent working out each week. The student gathers information from a random sample of male and female students on campus. The amount of time spent working out is normally distributed. The data are given below. -If significant, compute the effect size and interpret this.

A student is interested in whether students who study with others devote as much attention to their studies as do students who study alone. He believes those who study alone devote more attention to their studies. He randomly assigns subjects to either group or individual study conditions and has them read and study the same passage of information for the same amount of time. Subjects are then all given the same 10-item test on the material. Their scores appear below. Scores on the test represent interval/ratio data and are normally distributed. -If significant, draw a graph representing the data.

If a researcher reported for an independent-groups t test that t(22) = 2.69, p < .01, how many subjects were there in the study?

According to some research, males have better spatial skills than do females; and according to other research, females have better reading skills than males. A student is interested in determining which gender performs better on a word-search puzzle (a puzzle in which words are hidden vertically, horizontally, and diagonally within an array of letters) since this type of puzzle involves both spatial and reading skills. A sample of males and females volunteers to participate. They are given 10 minutes to work on a 50-word puzzle. The number of words correctly recognized is recorded for each subject, and the resulting data are as follows: Conduct the appropriate analysis of these data, and determine whether there are any significant differences.

For an independent-groups t test, effect size can be measured using:

A student is interested in whether students who study with others devote as much attention to their studies as do students who study alone. He believes those who study alone devote more attention to their studies. He randomly assigns subjects to either group or individual study conditions and has them read and study the same passage of information for the same amount of time. Subjects are then all given the same 10-item test on the material. Their scores appear below. Scores on the test represent interval/ratio data and are normally distributed. -If significant, compute the effect size and interpret this.

A student is interested in whether students who study with others devote as much attention to their studies as do students who study alone. He believes those who study alone devote more attention to their studies. He randomly assigns subjects to either group or individual study conditions and has them read and study the same passage of information for the same amount of time. Subjects are then all given the same 10-item test on the material. Their scores appear below. Scores on the test represent interval/ratio data and are normally distributed. -Conduct the appropriate analysis.