ES 350 Chapters 6-11 (EXAM 2)
For a group of normally distributed scores with a mean of 30 and a standard deviation of 6, the middle 68% of the scores will be between
24 and 36
The researcher obtained a significant F from the ANOVA. Partial 2 was found to be .30. This is interpreted to mean that Options: 9% of the total variance is accounted for by treatment 15% of the total variance is accounted for by error 30% of the total variance is accounted for by the treatments 70% of the total scores are due to the treatments
30% of the total variance is accounted for by the treatments
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? Options: 35% 49% 60% 70%
49%
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
Which one of the following statements does not describe an advantage of repeated measures?
Repeated measures can eliminate the influence of some unwanted variable.
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
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? Options: The test is highly correlated with the final grade in the course. 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. b and c only a, b, and c
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
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
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
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 discriminant function analysis, one is able to predict
membership in one of three or more groups
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 Options: two or more criteria from two or more predictors two or more criteria from one predictor one criterion from one predictor one criterion from two or more predictors
one criterion from two or more predictors
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 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
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? Options: t F r All of the above
All of the above
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.
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
Of the following, which is a nonparametric statistical test?
contingency coefficient
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
The standard deviation represents the
the spread of scores about the mean
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)
In logistic regression, one is able to predict
a binary outcome variable
What is the mode for the following set of numbers? (5, 10, 4, 1, 4, 5, 12, 8, 9, 4)
4
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
a contingency table
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
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
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
An important probability concept is relative frequency. Relative frequency is Options: the idea that a normal coin will land on heads 50 times out of 100 the idea that a coin that lands on heads 60 times out of 100 is rigged the idea that a normal coin may land on heads 40 times out of 100 all of the above
the idea that a normal coin may land on heads 40 times out of 100
Imagine you are rolling a 10-sided die that is equally weighted and with each side showing a number from one to ten. If you roll the die 10 times and you roll a three 4 of those 10 times, what does this tell you?
the relative frequency may not be the same as the theoretical frequency