ES 350 Test 2

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

Pearson product moment coefficient of correlation

Which hypothesis is stated in the null form?

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

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

chi square

What two things can statistics do?

establish significance and assess the magnitude of the effect

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

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

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

semantic differential scale

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

6 median=middle

In discriminant function analysis, one is able to predict

membership in one of three or more groups

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

In multiple regression, one is able to predict

one criterion from two or more predictors

For a group of normally distributed scores with a mean of 30 and standard deviation of 6, the middle 68% of the scores will be between

24 and 36

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

4. Mode=most occuring

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%

Why can't you just run multiple t-tests instead of running an ANOVA (and post-hoc tests if overall ANOVA is significant)?

Because you would be inflating your type I error rate (i.e., mistakenly increasing chances of finding statistical significance)

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.

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

Variables that show a relationship with one another may be statistically correlated. Referring to the figure below, 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

Which of the following is an example of snowball sampling?

asking college athletes to recruit their teammates

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

b and c only: The test is highly correlated with the final grade in the course. The test adequately samples what was covered in the course

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

coefficient alpha

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

effect size

A person'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

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

Power is defined as the probability of

rejecting a false null hypothesis

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

The standard deviation represents the

spread of scores about the mean

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, r

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

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 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

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

correlation

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

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

type II error