Questions and Answers of A Course In Statistics With R

To demonstrate the practical uses of basic learning principles, a psychologist with an interest in behavior modification collected data on a study designed to teach self-care skills to severely
Using the data from Exercise 14.1,a. Delete the data for the third session and run a (matched-sample) t test between Sessions 1 and 2.b. Now run a repeated-measures analysis of variance on the two
It is at least part of the folklore that repeated experience with any standardized test leads to better scores, even without any intervening study. Suppose that we obtain eight subjects and give them
Think of a nonstatistical example that could be used to explain to a student in an introductory statistics course why it is possible with any of the pairwise comparison tests to show that Group 1 is
In the analysis of Seligman et al. (1990) data on explanatory style (Table 13.15) you will note that there are somewhat more males than females in the Optimist group and more females than males in
Rerun the analysis in Exercise 13.31 but treat both variables as fixed and crossed. Show that the SSschool(code) in Exercise13.31 is the sum of SSschool and SSschool*code in this analysis. (Hint:If
An educational researcher wanted to test the hypothesis that schools that implemented strict dress codes produced students with higher academic performance. She randomly selected 7 schools in the
A psychologist interested in esthetics wanted to compare composers from the classical period to composers from the romantic period. He randomly selected four composers from each period, played one
Using the data from Exercise 13.28, reproduce the simple effects shown in Table 13.14.
The data for the three-way analysis of variance given in Table 13.14 are found on the Web.They are named Tab13–14.dat. The first three entries in each record represent the coding for A
Obtain the Tukey test for Dosage from the analysis of variance in Exercise 13.25. Interpret the results.
In Exercise 11.30 you calculated the average of the nine cell variances. How does that answer compare to the from Exercise 13.25?
Use any statistical package to run the two-way analysis of variance on Interval and Dosage for the data in Epineq.dat. Compare the results you obtain here with the results you obtained in Chapter 11,
In Chapter 2 we considered Sternberg’s experiment on the time it takes to report whether a test stimulus was part of a prior stimulus display. The independent variables were the number of stimuli
To study the effects of early experience on conditioning, an experimenter raised four groups of rats in the presence of (1) no special stimuli, (2) a tone stimulus, (3) a vibratory stimulus, and (4)
Calculate for the data in Exercise 13.5.
Calculate and for Exercise 13.5.
Calculate for the data in Exercise 13.1.
Calculate and for Exercise 13.1.
Use any standard computer software to analyze the data in Exercise 13.17. Compare your results with those you obtained previously.
Klemchuk, Bond, and Howell (1990) examined role-taking ability in younger and older children depending on whether or not they attended daycare. The dependent variable was a scaled role-taking score.
Assume that in Exercise 13.1 the last three participants in cell12 (Primiparous, LBW . 18)and the last two participants in cell23 (Multiparous, NBW) refused to give consent for their data to be used.
In Exercise 11.3 you ran a test between Groups 1 and 3 combined versus Groups 2 and 4 combined. How does that compare to testing the main effect of Level of processing in Exercise 13.11? Is there any
For the study in Exercise 13.5, to what would refer (if A were used to represent Area)?
In a study of memory processes, animals were tested in a one-trial avoidance-learning task.The animals were presented with a fear-producing stimulus on the learning trial as soon as they stepped
In Exercise 13.1 the design may have a major weakness from a practical point of view. Notice the group of multiparous mothers under 18 years of age. Without regard to the data, would you expect this
In a study of mother–infant interaction, mothers are rated by trained observers on the quality of their interactions with their infants. Mothers are classified on the basis of whether or not this
Find an example in the research literature of a study that used at least five different conditions, and create a data set that might have come from this experiment. Apply several of the techniques we
In Exercise 11.8 we considered a study by Foa et al. concerning therapy for victims of rape.The raw data can be found on the Web site at Ex12.30.dat. Apply the Benjamini and Hochberg LSU procedure to
Write up a brief report of the results computed for Exercises 12.1, 12.26, and 12.27.
Stone, Rudd, Ragozzino, and Gold (1992) investigated the role that glucose plays in memory. Mice were raised with a 12 hour light-on/light-off cycle, starting at 6:00 AM. During training mice were
Interpret the results in Exercise 12.23.
In Exercise 12.21 it would not have made much of a difference whether we combined the data across the three intervals or not. Under what conditions would you expect that it would make a big
Use any statistical package to apply the REGWQ (if available), and Scheffé procedures to the data from Introini-Collison and McGaugh (1986), described in the exercises for Chapter 11(p. 356). Do
Calculate the Benjamini-Hochberg test on the data in the example in Table 11.2, and compare your results to those you obtained for Exercise 12.10.
Fit linear and quadratic trend components to the Conti and Musty (1984) log transformed data in Table 11.6. The control condition received 0 mg of THC. For purposes of this example, assume that there
The Holm test is referred to as a modified sequentially rejective procedure. Why?
Apply Dunnett’s test to the log transformed data in Table 11.6.
Apply the Tukey procedure to the log transformed THC data from Table 11.6(p. 339). What is the maximum FW for this procedure?
Use the Scheffé test on the data in Exercise 12.13 to compare groups 1, 2, and 3 (combined)with groups 4 and 5 (combined). Then compare group 1 with groups 2, 3, and 4 (combined). (Hint: Go to the
Run Games and Howell (1976) approach to Tukey’s HSD procedure for unequal sample sizes on the data in Exercise 12.12.Group 12345 10 18 19 21 29 858797.4 8.98.6 7.2 9.3
Why might you be more interested in running specific contasts on the data referred to in Exercises 12.10 and 12.11?
Calculate the Tukey test on the data in the example in Table 11.2, and compare your results to those you obtained for Exercise 12.10.
Run a REGWQ test on the example given in Table 11.2(p. 324) and interpret the results.
Apply Holm’s multistage test to Exercise 12.1.
Repeat Exercise 12.7, using Holm’s multistage test. What differences do you find between these answers and the answers to Exercise 12.7?
Compute the Studentized range statistic for the two groups in Exercise 11.2, and show that it is equal to (where t is taken from Exercise 11.2b).
Using the data from Exercise 11.1, compute the linear contrasts for 5 versus (20 and 35)days and 20 versus 35 days, using a 5 .05 for each contrast. (Note that this and subsequent exercises refer to
Assume that the data that follow represent the effects of food and/or water deprivation on behavior in a learning task. Treatments 1 and 2 represent control conditions in which the animal received ad
With four groups you could have the means equally spaced along some continuum, or you could have three means approximately equal to each other and a fourth one different, or you could have two means
Gouzoulis-Mayfrank et al. (2000) examined task performance of users of the drug Ecstacy and compared that with a group of Cannabis users and a control group of Nonusers. There were 28 participants in
Strayer, Drews, and Couch (2006) ran a study in which they compared the driving behavior of a control group, a group that was at the legal limit for alcohol, and a group that was talking on a cell
Rerun Exercise 11.29, this time using Epineq.dat. (The results will differ somewhat because the data are different.) Calculate the average of the three error terms ( ) and show that this is equal to
Use the data in Epinuneq.dat to run three separate one-way analyses of variance, one at each retention interval. In each case, test the null hypothesis that the three dosage means are equal. Have
On the reasonable assumption that there are no important differences from one interval to the next, combine the data by ignoring the Interval variable and run the analysis of variance on Dosage. Use
In Exercise 7.46 you had data on students who had lost a parent through death, who came from a divorced household, or who grew up with two parents. You then ran three separate t tests comparing those
Davey, Startup, Zara, MacDonald, and Field (2003) were interested in the role of mood on the degree of compulsive checking in which a person engaged. (Compulsive checking is involved in a number of
Suppose that we wanted to run a study comparing recall of nouns and verbs. We present each subject with 25 nouns or 25 verbs and later ask for recall of the list. We look at both differences between
Would a transformation of Eysenck’s data in Table 11.2 be useful in terms of equalizing the variances? What transformation would you suggest applying, if any?
Darley and Latané (1968) recorded the speed with which subjects summoned help for a person in trouble. Subjects thought either that they were the only one listening to the person(Group 1, n 5 13),
Calculate and for the data in Exercise 11.17.
Apply a square-root transformation to the data in Table 11.5.
Howell and Huessy (1981) classified children as exhibiting (or not exhibiting) attention deficit disorder (ADD)-related behaviors in second, fourth, and fifth grade. The subjects were then sorted on
The computer printout in Exhibit 11.4 is from a JMP analysis of the data in Exercise 11.8.a. Compare the results with those you obtained in Exercise 11.8a.b. What can you tell from this printout that
Calculate and for the data in Exercise 11.8 and interpret the results.
Foa, Rothbaum, Riggs, and Murdock (1991) conducted a study evaluating four different types of therapy for rape victims. The Stress inoculation therapy (SIT) group received instructions on coping with
Calculate and for the data in Exercise 11.3.
Calculate and for the data in Exercise 11.2. Would you assume a fixed or a random model?
Refer to Exercise 11.2. Suppose that we collected additional data and had two more subjects in the Younger group, with scores of 13 and 15.a. Rerun the analysis of variance.b. Run an independent
Refer to Exercise 11.1. Assume that, for reasons beyond our control, neither the data for the last pup in the 5-day group nor the data for the last two pups in the 35-day group could be used. Rerun
Another way of looking at the data from Eysenck’s (1974) study is to compare four groups of subjects. One group consisted of Younger subjects who were presented the words to be recalled in a
Another aspect of the study by Eysenck (1974), referred to earlier, compared Younger and Older subjects on their ability to recall material in the face of instructions telling them that they would be
To investigate the maternal behavior of laboratory rats, we move the rat pup a fixed distance from the mother and record the time (in seconds) required for the mother to retrieve the pup to the nest.
Rosenthal and others (cited earlier) have argued that small effects, as indexed by a small, for example, can be important in certain situations. We would probably all agree that small effects could
In Exercise 7.48 using Mireault.dat, we compared the responses of students who had lost a parent and students who had not lost a parent in terms of their responses on the Global Symptom Index T score
Using Mireault’s data on this book’s Web site (Mireault.dat), calculate the point-biserial correlation between Gender and the Depression T score. Compare the relevant aspects of this question to
On page 302 I noted that Rosenthal and Rubin showed that an of .1024 actually represented a pretty impressive effect. They demonstrated that this would correspond to a of 20.48, and with 100 subjects
Assume in Exercise 10.14 that there were five entering clinical students. They produced the following data:Student 1: 1 4 2 6 5 3 9 10 7 8 Student 2: 4 3 2 5 7 1 10 8 6 9 Student 3: 1 5 2 6 4 3 8 10
In a study of diagnostic processes, entering clinical graduate students are shown a 20-minute videotape of children’s behavior and asked to rank order 10 behavioral events on the tape in the order
An investigator wants to arrange the 15 items on her scale of language impairment on the basis of the order in which language skills appear in development. Not being entirely confident that she has
An investigator is interested in the relationship between alcoholism and a childhood history of attention deficit disorder (ADD). He has collected the following data, where a 1 represents the
Visualize the data in Exercise 10.9 as fitting into a contingency table.a. Compute the chi-square on this table.b. Show the relationship between chi-square and .
Assume that the committee in Exercise 10.6 decided that a GPA-score cutoff of 3.00 would be appropriate. In other words, they classed everyone with a GPA of 3.00 or higher as acceptable and those
What do the slope and the intercept obtained in Exercise 10.7 represent?
Compute the regression equation for the data in Exercise 10.6. Show that the line defined by this equation passes through the means of the two groups.
A graduate-school admissions committee is concerned about the relationship between an applicant’s GPA in college and whether or not the individual eventually completes the requirements for a
Perform a t test on the data in Exercise 10.1 and show the relationship between this value of t and .
Why would it not make sense to calculate a biserial correlation on the data in Exercises 10.1 and 10.2?
Compare the results you obtained in Exercises 10.1 and 10.2. What can you conclude?
Because of a fortunate change in work schedules, we were able to reevaluate the subjects referred to in Exercise 10.1 for performance on the same tasks in the evening. The data are given below.Peak
Some people think that they do their best work in the morning, whereas others claim that they do their best work at night. We have dichotomized 20 office workers into morning or evening people (0 5
In a recent e-mail query, someone asked about how they should compare two air pollution monitors that sit side by side and collect data all day. They had the average reading per monitor for each of
In Chapter 2, I presented data on the speed of deciding whether a briefly presented digit was part of a comparison set and gave data from trials on which the comparison set had contained one, three,
Given a male and a female student who are both 5 6 , how much would they be expected to differ in weight? (Hint: Calculate a predicted weight for each of them using the regression equation specific
Using your own height and the appropriate regression equation from Exercise 9.31 or 9.32, predict your own weight. (If you are uncomfortable reporting your own weight, predict mine—I am 5 8 and
The following data are the actual heights and weights, referred to in this chapter, of female college students.a. Make a scatterplot of the data.b. Calculate the regression coefficients for these
The following data represent the actual heights and weights referred to earlier for male college students.a. Make a scatterplot of the data.b. Calculate the regression equation of weight predicted
One of the assumptions lying behind our use of regression is the assumption of homogeneity of variance in arrays. One way to examine the data for violations of this assumption is to calculate
Using the data referred to in Exercise 9.28,a. Calculate the correlations among all of the Brief Symptom Inventory subscales. (Hint:Virtually all statistical programs are able to calculate these
Using the data from Mireault (1990) in the file Mireault.dat, at http://www.uvm.edu/~dhowell/methods7//DataFiles/DataSets.html is there a relationship between how well a student performs in college

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