ES 350 Exam 2

Power is defined as the probability of

rejecting a false null hypothesis

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

type II error

What is the correct df (degrees of freedom) for a correlation between socioeconomic status and physical activity?

1

Which of the following is an example of snowball sampling?

asking college athletes to recruit their teammates

To calculate L for a correlation of two sets of ranked scores, the degrees of freedom ( N − 1) are multiplied by

r squared

The property of a distribution of scores that relates to how peaked or flat the curve is called

kurtosis

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

A confidence interval (CI) tells is how confident we can be that

the mean for a population lies within a range of scores

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

6

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

Pearson product moment coefficient of correlation

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

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

Four skill tests are tried as predictors of success in a tennis class. Each test correlates with later success as follows: test A, r= .27; test B, r= -.90; test C, r= -.40; test D, r= .6. The test that will most accurately predict success is

test B

For scores from a test to have good content validity, which of the following statements must be true?

The test adequately samples what was covered in the course. & The percentage of points for each topic area reflects the amount of emphasis given to that topic.

Which hypothesis is stated in the null form?

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

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

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

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

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

correlation

The significance of L determined when testing for differences between groups for ranked data is determined using the _____ table.

critical value of chi square

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

discriminant analysis

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

What two things can statistics do?

establish significance and assess the magnitude of the effect

In discriminant function analysis, one is able to predict

membership in one of three or more groups

If there is a correlation of .80 between a test of scholastic aptitude and performance on an achievement test, one can infer that

no causation can be inferred

Data such as sex, city of residence, or political party affiliation are what kind of measure?

nominal

Chi square is appropriate for which one of the following types of data?

observed frequencies

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

The type of scale that uses two adjectives, such as Worthless and Valuable, is a

semantic differential scale

What does finding a significant difference mean?

that your findings are reliable

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

the sampling technique that was used

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

A researcher wishes to know whether there is a significant difference in the number of knee injuries reported among four sports. How many degrees of freedom are there for this chi-square analysis?

3

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%

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

Repeated measures can eliminate the influence of some unwanted variable.

In logistic regression, one is able to predict

a binary outcome variable

If a researcher does not use random sampling, but then makes comparisons on potentially important variables between the sample and some larger group that it is supposed to represent, this is called

a post hoc justification

A null hypothesis is

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

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

The single score that best represents all the scores in a distribution is the definition of

central tendency

A statistical technique that tests for significant differences between observed and expected frequencies of occurrence is

chi square

Which of the following is a technique for providing information about the reliability of an instrument?

coefficient alpha

The author of a test of anxiety proceeds on the premise, based on the literature, that the performance of people with high anxiety suffers when they are under stress. In an experiment, the author finds that people who scored as highly anxious on the test performed more poorly on a stressful task. The test author maintained that this finding was evidence of what kind of validity?

construct

Comparing test items with the course objectives (course topics) checks which type of validity?

content

Of the following, which is a nonparametric statistical test?

contingency coefficient

A chi-square analysis compares the responses to a question on recreational preferences of males and females at three grade levels. The resulting two-way classification structure is called a

contingency table

A variable that is a mediator is one that

explains the effects of variable X on variable Y

Data from professional golfers support that the correlation between driving distance and driving accuracy is -0.60, p < .001. This means that

golfers who drive a longer distance are likely to be less accurate with 36% of the variance explained

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

A Pearson's correlation of .00 between two variables indicates

independence (no association) between the variables

A variable that is a moderator is one that

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

A teacher wishes to determine the reliability of three trials on a performance test. He uses ANOVA to obtain the reliability coefficient. This technique is called

intraclass correlation

If a thermometer measured the temperature in an oven as 400° five days in a row when the temperature was actually 337°, this measuring instrument would be considered

reliable but not valid

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

skewness

To determine whether data are normally distributed, one can test to see whether the curve is shifted to the left or right. This shift is called

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

After a population of 1,000 high school seniors is divided by sex and size of school attended, the random selection of a sample to represent these proportions of the population is called

stratified random sampling

Which option is a common test statistic?

t, F, and r

Randomly assigning the participants to a group allows you to assume:

that the groups are equivalent on their average scores for the dependent variable at the beginning of the experiment

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 all of the above