ES 350: Test 2 Study Guide

A measure that expresses the difference between the experimental and control group in standard deviation units is the:

effect size

A researcher decides to use an alpha of .01 and a power of .80. To determine the needed sample size the researcher must also ascertain the expected

effect size

Prediction studies use which of the following as the basic analysis technique?

Correlation

A statistical test that provides information about the relationship between two continuous variables is:

Person product moment coefficient of correlation

A variable that is a moderator is one that:

influences the strength of the effect of variable X on variable Y

Which of the following is an example of snowball sampling?

Asking college athletes to recruit their teammates

The researcher obtained a significant F from the ANOVA. Partial 2 was found to be .30. This is interpreted to mean that:

30% of the total variance is accounted for by the treatments

What is the mode for the following set of numbers? (5, 10, 4, 1, 4, 5, 12, 8, 9, 4)

4

A researcher finds a correlation of .70 between popularity ratings and self-concept scores. What percentage of common association can be inferred between the two variables?

49%

What is the median score for the following set of numbers? (3, 11, 8, 13, 5, 3, 6)

6

Variables that show a relationship with one another may be statistically correlated. Referring to figure 6.1 in the text, what might you expect in terms of the correlation?

A positive linear relationship

A null hypothesis is

A statistical hypothesis that assumes that there is no difference among the effects of treatments

Which option is a common test statistic?

All of the above

If the null hypothesis is false, one may assume the research hypothesis is the explanation for the results if:

All other possible explanations have been controlled

When the purpose of the research is to determine the effects of one independent variable (e.g., four groups) on one dependent variable (e.g., self-concept), the best choice of a statistical analysis is:

Analysis of variance

All statistical tests are based upon the same general comparison, which is

Between true variance and error variance

A study that has one independent variable with three levels and three dependent variables should be analyzed by:

Discriminant analysis

What two things can statistics do?

Establish the significance and assess the magnitude of the effect

Why is standard deviation important in terms of considering the sample?

If standard deviation is small, then the mean is likely to be a good representative score for the sample

In which of the following circumstances would you be likely to set alpha = .01 instead of alpha = .05?

If you were testing a drug that had the potential to save lives but also had serious side effects

If two measures have a high positive correlation, and a person has a low score on one measure, her score on the other measure is most likely to be:

Low

In multiple regression, one is able to predict:

One criterion from two or more predictors

Discriminant analysis differs from simple ANOVA such that discriminant analysis has:

One independent variable and two or more dependent variables

Which one of the following statements does not describe an advantage of repeated measures?

Repeated measures can eliminate the influence of some unwanted variable.

The term that describes the position (right or left; positive or negative) of the hump in the curve of a distribution is

Skewness

If a researcher finds a small difference in average test scores between a large sample (over 700) of experimental participants and a large sample (same size) of control participants, it is very likely that the difference is

Statistically significant but does not have a high degree of meaningfulness

An important probability concept is relative frequency. Relative frequency is:

The idea that a normal coin may land on heads 40 times out of 100

What determines if the findings from a sample can be generalized to a population?

The sampling technique that was used

Which hypothesis is stated in the null form?

There is no difference between the vocabulary scores of average- and high-ability students

When an experimenter states that the level of significance is at the .05 level, he or she is setting the probability of committing which type of error?

Type I error

If the researcher fails to reject the null hypothesis when there really is a difference, this is an example of a:

Type II error

In logistic regression, one is able to predict:

a binary outcome variable

A researcher sought to find out which of two exercises was more effective in building endurance. One group used exercise A, and another group used exercise B. At the end of study, the researcher should compare the two groups' scores with:

an independent samples t test

In discriminant function analysis, one is able to predict:

membership in one of three or more groups