Exam 9: Experimental Design and Analysis I

In an experimental study of the effects of exercise on stress, exercise is the​

Internal validity is​

Which of the following t test results has the greatest chance of statistical significance?

Single-blind experiments help to control for ____ effects whereas double-blind experiments help to control for _____ effects.​

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

When we can generalize from the sample used in a study to the population of interest, we say that the study has _____ validity.

Baseline is to treatment as _____ is to _____.​

To say that an experiment contains a confound means that

In an experimental study of the effects of exercise on stress, subjects are randomly assigned to either the no exercise group or the exercise group. These groups represent the _____ and the _____, respectively.

When subjects are lost differentially from the experimental and control groups, any observed effect may be due to

Sometimes it is difficult to generalize the results of a study to the population because of the _____ problem.

A student is interested in whether students who study with others devote at 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 participants to either group or individual study conditions and has them read and study the same passage of information for the same amount of time. Participants 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. a) What statistical test should be used to analyze these data? b) Identify H₀ and H_a for this study. c) Conduct the appropriate analysis. d) Should H₀ be rejected? What should the researcher conclude? e) If significant, compute the effect size and interpret this. f) If significant, draw a graph representing the data. g) Calculate the 95% CI.

Which of the following is not an assumption of the t test for independent groups?

Changes that occur naturally in the subjects over time could result in the confound of​

If an independent-groups t test has seven participants in each group, then the degrees of freedom are​

Independent variable is to dependent variable as _____ is to _____.

The best advice for those considering retaking the SAT is that if your score was below average you probably ____ retake the test, and if your score was above average you probably ____ retake the test due to _____.​

Alison's bathroom scale will not register a weight of more than 130 pounds. Alison does not realize this, and therefore is unaware that she has put on a few pounds until she begins to notice how tight her clothes are. This illustrates the confound of a _____ effect.​

Differentiate between an exact replication, a systematic replication, and a conceptual replication.

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 volunteer to participate and 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. ​