Questions and Answers of Fundamentals Of Statistics

I drew 50 samples of five scores each from the same population that the data in Exercise 12.1 came from, and calculated the mean of each sample. The means are shown below. Plot the distribution of
Compare the means and the standard deviations for the distribution of digits in Exercise 12.1 and the sampling distribution of the mean in Exercise 12.2.a) What would the Central Limit Theorem lead
Use R to repeat Exercises 12.1 and 12.2. (The code for this exercise can be found on the chapter’s Web page along with other pieces of code. This code will generate its own set of 100 random
In what way would the result in Exercise 12.2 differ if you had drawn 50 samples of size 15? (If you answered Exercise 12.4, you can easily modify it to answer this question.)Exercise 12.2I drew 50
Why do the data in Exercise 12.6 not really speak to the issue of whether education in North Dakota is generally in good shape?Exercise 12.6In Table 11.1 in Chapter 11 we saw data on the state means
In Exercise 5.21 we saw, among other things, the weight gain of each of 29 anorexic girls who received cognitive behavioral therapy. What null hypothesis would likely be testing in this
The data referred to in Exercise 12.10 (in pounds gained) follow. Run the appropriate t test and draw the appropriate conclusions.Exercise 12.10In Exercise 5.21 we saw, among other things, the weight
Compute 95% confidence limits on μ for the data in Exercise 12.11.Exercise 12.11The data referred to in Exercise 12.10 (in pounds gained) follow. Run the appropriate t test and draw the appropriate
As I entered the data into an R file for Exercise 12.11 I became a bit concerned about what they meant. Can you suggest a reason for my concern?Exercise 12.11The data referred to in Exercise 12.10
Use one of the free statistics programs that we have been using and reproduce the results for Exercises 12.11 and 12.12. This is an example where it is probably easier to enter the data by hand.
Compute a measure of effect size for the data in Exercise 12.11.Exercise 12.11The data referred to in Exercise 12.10 (in pounds gained) follow. Run the appropriate t test and draw the appropriate
For the IQ data on females in data set Add.dat on the website, test the null hypothesis thatμfemale = 100. You can use SPSS or R, or any other program you have.
In Exercise 12.16 you probably solved for t instead of z. Why was that necessary?Exercise 12.16For the IQ data on females in data set Add.dat on the website, test the null hypothesis thatμfemale =
Compute the 95% confidence limits on mean anxiety for the data in Exercise 12.19.Exercise 12.19In Section 12.3 we ran a t test to test the hypothesis that young children under stress give what they
Are the confidence limits that you calculated in Exercise 12.20 consistent with the results of the t test in Exercise 12.19?Exercise 12.19In Section 12.3 we ran a t test to test the hypothesis that
Write a brief paragraph describing the research project in Exercise 12.19 and its results.Exercise 12.19In Section 12.3 we ran a t test to test the hypothesis that young children under stress give
Have you ever wondered how you would do on the SATs if you didn’t even bother to read the passage you were asked about?5 Katz, Lautenschlager, Blackburn, and Harris (1990) asked students to answer
Make a stem-and-leaf display for the data in Exercise 3.1 using a reasonable number of intervals.Exercise 3.1Have you ever wondered how you would do on the SATs if you didn’t even bother to read
Use R to reproduce the stem-and-leaf display of the data in Figure 3.3. The code can be found in Section 3.2. Figure 3.3 Stem-and-leaf display for the mental rotation data The decimal point is one
If students had just guessed in the Katz et al. study, they would have been expected to earn a score of approximately 20. Do these students appear to do better than chance even when they haven’t
As part of the study described in Exercise 3.1, the experimenters obtained the same kind of data from a smaller group who had read the passage before answering the questions (called the Passage
In Chapter 2, Exercise 2.4, I asked those with access to SPSS to go to the book’s website, find the short SPSS manual, and download the apgar. sav file. If you have SPSS but did not do that
Use SPSS or R to load and plot the data on mental rotation reaction times that were presented(in part) in Table 3.1. These data can be found in the data files of this book’s website as Tab3-1.dat,
Go to the Web pages at http://www.uvm.edu/~dhowell/fundamentals9/Supplements/IntroducingR.html. Skim that page for information on R and then read the section on“Simple Examples,”
Create a histogram for the data for GPA in Add.dat, using reasonable intervals. You can do this by hand or by using any available software.Refer to a large data set in Appendix D. The data can also
Create a stem-and-leaf display for the ADDSC score in Add.dat, again using any available software.Refer to a large data set in Appendix D. The data can also be downloaded from the Web at
In some stem-and-leaf displays with one or two unusually low values, the first stem is often written as LOW, with the complete values in the leaf section. Why and when might we do this?
In Table 3.1 the reaction-time data are broken down by the degrees of rotation separating the objects. (You may want to sort the data by this variable.) Use SPSS or another computer program to plot
When Krantz devised the experiment that produced the data in Table 3.1, he was interested in seeing whether the required degree of mental rotation influenced reaction time. From the answer to
In addition to comparing the reaction times as a function of rotation, how else might you use these data to draw conclusions about how people process information?
The following data represent U.S. college enrollments by census categories as measured in 1982, 1991, and 2005. (The 2005 data are approximate.) Plot the data in a form that represents the changing
The New York Times (March 16, 2009) reported that approximately 3% of the population of Washington, D.C., was living with HIV/AIDS. Search the Web for worldwide statistics that would put that number
The following data represent the total number of U.S. households, the number of households headed by women, and family size from 1960 to 1990. Present these data in a way that reveals any changes in
Modify the R code given for Figure 3.6 to reproduce the figure in the previous exercise. Figure 3.5 Average reaction time as a function of whether or not the judgment was correct Mean RTsec 2.00
Repeat Exercise 3.23, but this time plot changes in family size.Exercise 3.23Modify the R code given for Figure 3.6 to reproduce the figure in the previous exercise. Figure 3.5 Average reaction time
Moran (1974) presented data on the relationship, for Australian births, between maternal age and Down syndrome (a serious handicapping condition on which psychologists have done a lot of work). The
Further information on Down Syndrome and maternal age can be found at https://www.aafp.org/afp/20000815/825.html
Psychologists concerned about self-injurious behaviors (e.g., smoking, eating fatty diets, drug abuse, etc.) worry about the effects of maternal smoking on the incidence of low birth weight babies,
Additional (and more recent) data on smoking and low birthweight (in Switzerland) can be found at http://www.smw.ch/docs/pdf200x/2005/35/smw-11122.pdf Plot those data (and/or other data that you can
The Journal of Statistics Education maintains a fairly extensive collection of data on a wide variety of topics. Each data set is accompanied by a description of the data and how they might be used.
The following graph plots the data on life expectancy of White and Black females. What conclusions would you draw from this graph? (Comparable data for men can be found at
Using the data on men found at the website given above, plot that line graph in R. To get both lines on the same graph, draw one plot, enter “par = new”, and then draw the second plot.
Use R to reproduce display Figure 3.4 as a boxplot instead of back-to-back stem-and-leaf displays.The command is boxplot(y ~ x), where “~” is read “as a function of” and x and y are the
Use R to produce the back-to-back stem-and-leaf display in Figure 3.4—stored as Fig3-4.dat.This is a tricky one, and it is more of a puzzle to work on. Can you get it to work? I suggest that you
Which of the measures of central tendency are you most likely to see reported in the popular press?
What do we report when a distribution has two distinct, and nonadjacent, modes?
When is the median most useful?
Give two advantages of the mean relative to the other measures.
Why do we use trimmed samples?
What is a good percentage to trim from a sample?
Do the data from the Seeing Statistics example support what perceptual psychology would expect us to see?
The measures of central tendency for the data on Katz’s study who did not read the passages were given in the SPSS printout in Figure 4.1. Compare those answers with the answers to Exercises 4.1.
Make up a set of data for which the mean is greater than the median.
Make up a positively skewed set of data. Does the mean fall above or below the median?
Why would it not make any sense to calculate the mean for SEX or ENGL in Appendix D?If we did go ahead and compute the mean for SEX, what would the value of really represent?Appendix D (X-1)
With reference to Exercise 4.13, if people take longer to process an image that has been both reversed and rotated, then the mean reaction time should depend on whether or not the comparison stimulus
Why is the mode an acceptable measure for nominal data? Why are the mean and the median not acceptable measures for nominal data?
Why do you think that I did not ask you to calculate the mode?
Search the Internet for sources of information about measures of central tendency. What do you find there that was not covered in this chapter?
Use R to calculate the mean and median of the data in Exercise 4.1. The commands are of the form xbar Exercise 4.1As part of the Katz et al. (1990) study that examined test performance on a passage
The Internet is a great resource when you don’t know how to do something. Search the Internet to find out how to use SPSS to calculate the mode of a set of data. You can just go to any search
The bases package for R does not have a command such as “a
a) Calculate the 10% trimmed mean for the data on test performance in Figure 4.1. (Remember that 10% trimming means removing the 10% of the scores at each end of the distribution.)b) Assume that you
I have suggested that if you don’t understand something I write, go to any search engine and find something better. In Chapter 2 I admitted that it was pretty easy to define a dependent variable,
An outlier is
What is a major problem with the interquartile range?
How would you describe the interquartile range with respect to trimmed samples?
What is wrong with the average deviation from the mean?
Why is the standard deviation a better measure than the variance when we are tryingto describe data?
Why do we divide by N – 1 instead of N when we are computing the variance and thestandard deviation?
What do we mean by an “unbiased” estimate of a parameter?
We refer to quantities like N – 1 as _____.
What is the “quartile location?”
How do we determine the values that will be the end of the whiskers in a boxplot?
What is a Winsorized sample?
Repeat exercises 5.1 and 5.2 using R. (It is easiest if you use the “describe” command from the “psych” library.)Exercises 5.1Calculate the range, the variance, and the standard deviation for
In Exercise 5.1, what percentage of the scores fall within two standard deviations from the mean?Exercises 5.1Calculate the range, the variance, and the standard deviation for data that Katz et al.
In Exercise 5.2, what percentage of the scores fall within two standard deviations from the mean?Exercises 5.2Calculate the range, the variance, and the standard deviation for the Katz et al. data on
Given the data you created in Exercise 5.6, show that multiplying or dividing by a constant multiplies or divides the standard deviation by that constant. How does this relate to what happens to the
Using what you have learned from Exercises 5.6 and 5.7, transform the following set of data to a new set with a standard deviation of 1.00.5 8 3 8 6 9 9 7Exercise 5.6Create a small data set of about
Use the answers to Exercises 5.6 and 5.7 to modify the answer to Exercise 5.8 to have a mean of 0 and a standard deviation of 1.00.Exercise 5.6Create a small data set of about seven scores and
Create a boxplot for the data in Exercise 5.1.Exercises 5.1Calculate the range, the variance, and the standard deviation for data that Katz et al. collected on SAT performance without reading the
Create a boxplot for the data in Exercise 5.2 using R or SPSS if possible.Exercises 5.2Calculate the range, the variance, and the standard deviation for the Katz et al. data on SAT performance after
Using the data for the variable ENGG in Appendix D(a) Calculate the variance and the standard deviation for ENGG.(b) These measures should be greater than the corresponding measures on GPA. Can you
Instead of adding a score equal to the mean (as in Exercise 5.15), add a score of 40 to the data used in Exercise 5.1. How does this score affect the answers to Exercise 5.1?Exercises 5.1Calculate
Use SPSS, R, or other software to draw a set of boxplots to illustrate the effect of increase in the angle of rotation in the Mental Rotation data set. The data can be found at
Everitt, as reported in Hand et al. (1994), presented data on the amount of weight gained by 72 anorexic girls under one of three treatment conditions. The conditions were Cognitive Behavior Therapy,
Compare the mean, standard deviation, and variance for the data in Exercise 5.1 with their trimmed and Winsorized counterparts.Exercises 5.1Calculate the range, the variance, and the standard
Compare the mean, standard deviation, and variance for the data for the Cognitive Behavior condition in Exercise 5.21 with their 20% trimmed and Winsorized counterparts. Why is the Winsorized
The “ordinate” is what we have previously called the _____ axis.
What is special about a standard normal distribution?
What does N(μ, σ2) represent?
A linear transformation is one in which _____.
A _____ represents the number of standard deviations above or below the mean.
Probable limits are used to _____.
How do we go from z back to the corresponding X?
What do we mean by “standardization?”
What is the 32nd percentile?
What are the mean and standard deviation of T scores?
Assuming that the following data represent a population of X values with μ = 4 and σ = 1.58:X = 1 2 2 3 3 3 4 4 4 4 5 5 5 6 6 7a) Plot the distribution as given.b) Convert the distribution in (a)

Showing 300 - 400 of 944