# STATS FINAL PT.III

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1. The following source table depicts the results of a fictional study investigating whether the number of hours of sleep a person gets varies with his or her gender (male, female) and with the number of cups of coffee he or she consumes in a day. Equal numbers of men and women were randomly assigned to drink 1, 2, or 3 cups of coffee during the course of a day and then record the number of hours they slept that night.

Table: Coffee and Sleep

(Table: Coffee and Sleep) Using a p level of 0.05, the critical value for the main effect of gender is ________, and the critical value for the main effect of cups of coffee is ________.

A) 4.13; 3.28
B) 4.17; 3.32
C) 3.32; 3.32
D) 4.13; 4.13
B) 4.17; 3.32
(this multiple choice question has been scrambled)
2. (Table: Coffee and Sleep) What was the sample size for the entire study?

A) N = 30
B) N = 35
C) N = 36
D) N = 40
C) N = 36
(this multiple choice question has been scrambled)
3. (Table: Coffee and Sleep) Using a p level of 0.05, what are the significant effects?

A) None of the effects is significant.
B) a main effect of the number of cups of coffee and an interaction between gender and the number of cups of coffee
C) a main effect of gender and an interaction between gender and the number of cups of coffee
D) a main effect of the number of cups of coffee and no other effects
D) a main effect of the number of cups of coffee and no other effects
(this multiple choice question has been scrambled)
4. The degrees of freedom for the interaction in a two-way ANOVA is calculated by:

A) multiplying together the degrees of freedom associated with each of the main effects.
B) adding together the degrees of freedom associated with each of the main effects.
C) subtracting the degrees of freedom for the first main effect from that of the second main effect.
D) subtracting a single participant from each cell of the study and then adding the results for all the cells.
A) multiplying together the degrees of freedom associated with each of the main effects.
(this multiple choice question has been scrambled)
5. A researcher performs a 2 X 3 ANOVA with 5 participants in each cell of the study design. What is the degrees of freedom for the interaction?

A) 3
B) 6
C) 2
D) 5
C) 2
(this multiple choice question has been scrambled)
6. Which of the following numbers would indicate the strongest relationship between two variables?

A) 0.59
B) –0.72
C) –0.25
D) 0.65
B) –0.72
(this multiple choice question has been scrambled)
7. Which of the following numbers would represent a perfect correlation?

A) 0
B) –1.00
C) 1.00
D) –1.00 or 1.00
D) –1.00 or 1.00
(this multiple choice question has been scrambled)
8. Which of the following values of r allows a perfect prediction of scores on one variable from knowledge of scores on the other variable?

A) 2.00
B) –1.00
C) 0
D) 0.50
B) –1.00
(this multiple choice question has been scrambled)
9. If all the points on a scatterplot fall on a single line:

A) the relation between the variables is perfect.
B) there is no relation between the variables.
C) there is a positive correlation between the two variables.
D) the variables are causally related.
A) the relation between the variables is perfect.
(this multiple choice question has been scrambled)
10. Suppose a researcher discovers that following a Mediterranean diet is negatively correlated with risk of developing cancer. Which of the statements logically follows from this information?

A) Eating a Mediterranean diet increases the risk of developing cancer.
B) People who eat a Mediterranean diet are less likely to have cancer.
C) Eating a Mediterranean diet reduces the risk of developing cancer.
D) People who eat a Mediterranean diet are more likely to have cancer.
B) People who eat a Mediterranean diet are less likely to have cancer.
(this multiple choice question has been scrambled)
11. Why do correlation coefficients greater than 0.50 rarely occur in the social sciences?

A) Social scientists have not yet discovered the variables that are the best predictors of human behavior.
B) Social scientists fail to construct experiments carefully enough to detect larger correlations.
C) Human behavior is the product of many interacting variables; any single variable will be limited in its association with a behavior.
D) The highest value a correlation coefficient can take on is 0.60.
C) Human behavior is the product of many interacting variables; any single variable will be limited in its association with a behavior.
(this multiple choice question has been scrambled)
12. Using the Pearson correlation coefficient to analyze the relationship between two variables is only appropriate if:

A) both variables are measured on an ordinal scale.
B) both variables are measured on at least an interval scale.
C) the variables are linearly related.
D) the variables are linearly related and they are both measured on at least an interval scale.
D) the variables are linearly related and they are both measured on at least an interval scale.
(this multiple choice question has been scrambled)
13. A ________ is a graphical representation of the relation between two variables.

A) correlation coefficient
B) histogram
C) scatterplot
D) polygon
C) scatterplot
(this multiple choice question has been scrambled)
14. Identify the formula for the Pearson correlation
coefficient.
A
15. What is the null hypothesis when testing for significance using the Pearson correlation coefficient?
B
16. Based on research with her patients, Dr. Sabine knows that the correlation coefficient between scores on an anxiety scale and comfort at a social gathering is –0.35. If the critical value for r is 0.330, what would you conclude?

A) Scores on the anxiety scale are causally related to feelings of comfort in a social gathering.
B) Scores on the anxiety scale are not significantly related to feelings of comfort in a social gathering.
C) The null hypothesis should be retained.
D) Scores on the anxiety scale are significantly related to feelings of comfort in a social gathering.
D) Scores on the anxiety scale are significantly related to feelings of comfort in a social gathering.
(this multiple choice question has been scrambled)
17. A Pearson correlation coefficient is calculated for 48 individuals. What value of df should be used to determine statistical significance in hypothesis testing?

A) 45
B) 46
C) 47
D) 48
B) 46
(this multiple choice question has been scrambled)
18. In a reanalysis of published studies, Twenge and Im (2007) found that for the time period of 1958 to 2001, the need for social approval of people in the United States was positively correlated with changes in the Dow Jones Industrial Average during that same period (the correlation coefficient was 0.10). This means that:

A) as the need for social approval went up, the Dow Jones decreased.
B) the need for social approval prevented people from investing money in the stock market.
C) as the need for social approval went up, the Dow Jones also increased.
D) the need for social approval caused people to invest more money in the stock market.
C) as the need for social approval went up, the Dow Jones also increased.
(this multiple choice question has been scrambled)
19. According to the 2003–2004 annual report of the Association of Medical and Graduate Departments of Biochemistry, the average stipend for a postdoctoral trainee in biochemistry was \$31,331, with a standard deviation of \$3,942. Assuming that these data are normally distributed, what was the stipend for a trainee in the 76th percentile?
\$34,090.40
20. It
is known that the population mean for the verbal section of the SAT is 500,
with a standard deviation of 100. In 2006, the sample of 100 students taking
the SAT whose family income was less than \$10,000 had a verbal score of 429.
Perform a one-tailed hypothesis test to determine whether the group whose
family income was less than \$10,000 scored significantly lower on average
than the population.
21. The average age for licensed drivers in a county is  = 42.6,  = 12, and the distribution is approximately normal. A county police officer was interested in whether the average age of drivers receiving speeding tickets differed from the average age of the driving population. She obtained a sample of N = 16 drivers with speeding tickets. The average age for this sample was M = 34.4.

Calculate the effect size for this study.
22. Mehl (2007) published a study in the journal Science reporting the results of an extensive study of 396 men and women comparing the number of words uttered per day by each sex. Volunteer participants wore inconspicuous recording devices that recorded their daily word usage. On average, women uttered 16,201 words per day (SD = 1779.45), and men uttered 15,993 words per day (SD = 2224.61).

a. Assume equal sample sizes and calculate the point estimate for the difference between the means and the 90% confidence interval around the point estimate.
b. Make a decision regarding the null hypothesis on the basis of this confidence interval.
23. Using the following information, calculate an effect size using Cohen's d for a paired-samples t test.

Sample mean difference = 14
Population mean difference = 0
s = 5.110
24. (Table: Infant Attention) A researcher is interested in whether infants' attention to their mothers' voices increases in the first week of life. The researcher selects 15 full-term infants in normal health who experienced uncomplicated deliveries and tests the number of seconds the infants oriented in the direction of their mother's voice on Day 1 and on Day 7 after delivery. The fictional data follow. Test the hypothesis using a directional hypothesis test.
25. Dr. Hogan was interested in the effects of test anxiety on concentration abilities. He measured student anxiety levels when the students arrived at his laboratory and then again immediately before taking an examination using an anxiety questionnaire. Dr. Hogan hypothesized that participants in his study would have higher anxiety scores immediately prior to the completion of the exam compared to when they first came in. As hypothesized, Dr. Hogan found that participants' anxiety scores were significantly higher immediately prior to the examination compared to baseline scores. As a result of this information, what type of t test was Dr. Hogan most likely to use to test his hypothesis? Is Dr. Hogan's hypothesis test one-tailed or two-tailed? Explain your answers.
26. A
researcher is interested in whether there are significant differences between
men and women and religious preferences. In planning his hypothesis tests,
the researcher identified gender as the independent variable and religious
preferences (e.g., Catholic, Protestant, Jewish) as his dependent variable.
Can the researcher use an independent-samples t test to test his
hypothesis? Why or why not?
27. (Table:
Diets) An article in the journal Applied Nutritional Investigation
reported the results of a comparison of two different weight-loss programs
(Liao, 2007). In the study, obese participants were randomly assigned to one of
two groups: (1) the soy group, a low-calorie group that ate only soy-based
proteins, or (2) the traditional group, a low-calorie group that received 2/3
of their protein from animal products and 1/3 from plant products. One of the
dependent measures collected was the amount of body fat loss as a percentage of
initial body weight. Fictional data on the percent of body fat loss appears in
the table. These data produce results similar to those of the 2007 study (note
that a smaller n than that used in the study is presented for ease of
calculation). Test the hypothesis using the data below.
28. (Table: Herbal Remedies) A researcher is interested in whether herbal remedies are effective in relieving allergies, and if so, which ones are most effective. The researcher takes a group of 20 allergy sufferers and randomly assigns each one to receive herbal tea, a homeopathic administration of allergens, a traditional antihistamine, or a placebo pill. The dependent measure is the number of allergy complaints by patients during weeks 2 and 3 of the treatments. Perform the six steps of hypothesis testing on the following set of fictional data.
29. Imagine that a researcher is interested in investigating whether the number of hours of sleep a person gets varies with gender (male, female) and with the number of cups of coffee the person consumes in a day. Equal numbers of men and women were asked to drink 1, 2, and 3 cups of coffee during the course of a day (on different days) and then record the number of hours they slept that night.

a. Identify the independent variables and the level of each independent variable.
b. What is the dependent variable?
c. What kind of ANOVA would be used to analyze these data?
d. Draw a table depicting the cells of the study.
30. Draw a scatterplot and compute the Pearson correlation coefficient for the following set of data:
 Author: yogalindo ID: 301406 Card Set: STATS FINAL PT.III Updated: 2015-04-23 20:26:36 Tags: statistics Folders: Description: study guide pt. 3 Show Answers: