350 exam 2
What is the mode for the following set of numbers? (5, 10, 4, 1, 4, 5, 12, 8, 9, 4)
4
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
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?
(t,F,r)All of the above
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
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
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
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
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
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
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
Prediction studies use which of the following as the basic analysis technique?
correlation
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 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 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
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 below
low
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
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 type of scale that uses two adjectives, such as Worthless and Valuable, is a
semantic differential scale
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
The term that describes the position (right or left; positive or negative) of the hump in the curve of a distribution is
skewness
A statistical test that provides information about the relationship between two continuous variables is
Pearson product moment coefficient of correlation
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 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.
Which hypothesis is stated in the null form?
There is no difference between the vocabulary scores of average- and high-ability students.
In discriminant function analysis, one is able to predict
membership in one of three or more groups
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