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