Ask Question, Ask an Expert

+1-415-315-9853

info@mywordsolution.com

Ask Statistics and Probability Expert

Problem 1

Use the following four data sets for problem 1 (from Anscombe (1973), American Statistician).  Be aware that this is a very interesting series of data sets with some special properties. I do not have data files for these data, so you’ll need to enter it by hand. If you want to challenge yourself, try to copy and paste this data into an excel sheet or text file and then bring it in through SPSS.

652_Data set.jpg

(a) For each of the four data sets separately:  find out the Pearson r and the regression equation,  = b0 + b1X; find out R2 and associated test of significance. Test b1 for significance. Briefly prepare what you would conclude about the comparison of these datasets from these analyses.

(b) For data set 1 and data set 3, compute the outlier diagnostics. Are there are any outliers? If so, please describe.

(c) Comment on what lessons have you learned (or should have learned) from this problem. That is, why did I pick these data and ask you to specifically do steps a, &b? When looking at the data analysis as a whole, what lesson should this problem teach?

Problem 2

The following are actual data showing the latitude of a sample of major cities in the northern hemisphere and their mean high annual temperature.

latitude(X)    mean high temp(Y)
1. Acapulco         17                      88
2. Algiers            37                      76
3. Berlin             53                       55
4. Bogota            5                       66
5. Montreal         46                      50
6. Oslo               60                      50
7. Rome             42                      71
8. Saigon*          11                     90
* Now known as Ho Chi Minh City.

(a) Compute and prepare the prediction regression equation(note: do not just refer to spss output—prepare out the full equations)

(i)  In unstandardized form (For every increase in ___, x goes up by ____)
(ii) In standardized form(units)

(b) find out the predicted mean temperature (degrees F) for each city. 

(c) Test the b1 coefficient; find out and test R2

Report results of these tests in a short APA results-style paragraph

(d) Plot Y (vertical axis) vs. X (horizontal axis) showing best fitting straight line

(e) Report standard measures of leverage (X space), studentized deleted residuals (Y space), and SDFFITS (influence) for each city.

(f) Examine your plots.  Consider your expectations, the obtained values of r and b1, the plots, and your outlier statistics.  Do any of the cities appear to be having a particularly strong influence on the results?  If so, which one(s) and why?

(g) Drop the point(s) identified in (f) from the data analysis and using SPSS re-compute r and b1.  Test the new b1 coefficient; find out and test the new R2.Report the results of these tests in a short APA results-style paragraph, and describehow do the results change?

(h) In general, are you justified in dropping data?  When is it appropriate vs. inappropriate? Comment on why this procedure of dropping one or more cities may or may not be appropriate in the present case (Hint: consider the altitudes—not latitudes-- of the cities).

Problem 3

The following data are measures of triceps skinfold thickness (X1), thigh circumference (X2), and midarm circumference (X3).  These three variables are used to predict percentage of body fat (Y). You can also find the data on beachboard (titled “bodyfat”).

945_Skinfold thickness.jpg

(a)  Compute the regression of Y on X1. 

(b)  Compute the regression of Y on X2.

(c)  Compute the regression of Y on X1, X2

(d)  Compute the regression of Y on X1, X2, X3

In each case, report the results in a brief APA results-style paragraph. For each individual predictor remember to report bs, standard error of each b (or confidence intervals), t test; and for each overall model report F test,df, and R2.

(e) Compute the correlation matrix of the predictors (X1 X3)

(f) Compute the tolerance (or VIF) of each predictor for the equation (d) which includes all 3 predictors.

(g) Examine the outlier statistics for the X space, Y space, and influence (including DFBETAS for each predictor).  Identify the highly discrepant observations, if any.

(h) Comment on what you have learned about this data set, particularly with regard to the three predictors, and interpret the results.

Problem 4

Data for problem 4 are provided by Tabachnik&Fidell (2007), and represent a subset of variables that were collected as part of a year-long study on the relationship between stressful life events and mental and physical health (for more details on this study see Appendix B1 of Tabachnik&Fidell , 2007 or see Hoffman &Fidell, 1979, where these data were initially published). You can find the five variable data set (N= 465) on beachboard(titled “tbregress”). Here is a brief description of the variables:

subjno: Subject number
timedrs: number of visits to health professionals over the course of the study
phyheal: self reported frequency count of problems with various body systems (circulation, digestion, etc.), general description of health
menheal: frequency count of mental health problems (feeling somewhat apart, can’t get along, etc.)

stress: weighted items reflecting number and importance of change in life situation

Use multiple regression and correlation analyses to understand what the data from these variables tell us about the relationships between mental and physical health. Remember to use data centering to make sense of your data (when you want to make the intercept values meaningful). Clearly state the research problems that you want to test in these data and describe the results from the statistics you used to test your models. prepare your work as a results section, organized by the research problem you are testing.

Statistics and Probability, Statistics

  • Category:- Statistics and Probability
  • Reference No.:- M91094

Have any Question? 


Related Questions in Statistics and Probability

At a school pep rally a group of sophomore students

At a school pep rally, a group of sophomore students organized a free raffle for prizes. They claim that they put the names of all the students in the school in the basket and that they randomly drew 36 names out of this ...

For each of the following three cases explain i the

For each of the following three cases, explain (i) the hypotheses with a plausible definition of p1 and p2, (ii) whether or not the data indicate practical significance (use common sense and/or general knowledge), and (i ...

A history class is comprised of 8 female and 6 male

A history class is comprised of 8 female and 6 male students. If the instructor of the class randomly chooses 5 students from the class for an oral exam, what is the probability that 2 female students and 3 male students ...

Prove that if romeo and juliet are matched to each other

Prove that if Romeo and Juliet are matched to each other under both the men's courtship and the women's courtship algorithms, then they are matched to each other under any stable matching.

Plot four different regression graphs x v y tomatometer v

Plot four different regression graphs (X v Y): Tomatometer v Audience, Budget v Gross, Budget v Tomatometer, Audience v Gross and find the best-fit line equation and correlation coefficient (r-value) for each one. X repr ...

Starting in the 10th century movements to reform the church

Starting in the 10th century, movements to reform the church began. Why was the church in need of reform, and what were the consequences of the Gregorian Reforms? How did these reforms change society? 1 and a half page e ...

Subway footlongs are supposed to be 12 inches long you

Subway footlongs are supposed to be 12 inches long. You strongly suspect that Subway is up to its old tricks and is reducing the size of its delicious sandwiches. For your research, you randomly sample Subways and eat 10 ...

Imagine that the equation for predicting y from x is y 112

Imagine that the equation for predicting y from x is y = 1.12 - .47x. How would you use this equation to predict a particular individual's score?

Simple takes about 25 minutes to answer in a study

Simple! (Takes about 25 minutes to answer.) In a study evaluating "Why minority males graduate American high-schools at lower rates than their counterparts", the following is needed: 1) Envisioned Quantitative Design 2) ...

You are playing blackjack in a casino the casino is using a

You are playing blackjack in a casino. The casino is using a single, 52 card deck. Shuffling the deck takes time. So rather than shuffling the deck after each hand, the casino deals three hands before shuffling. The used ...

  • 4,153,160 Questions Asked
  • 13,132 Experts
  • 2,558,936 Questions Answered

Ask Experts for help!!

Looking for Assignment Help?

Start excelling in your Courses, Get help with Assignment

Write us your full requirement for evaluation and you will receive response within 20 minutes turnaround time.

Ask Now Help with Problems, Get a Best Answer

Section onea in an atwood machine suppose two objects of

SECTION ONE (a) In an Atwood Machine, suppose two objects of unequal mass are hung vertically over a frictionless

Part 1you work in hr for a company that operates a factory

Part 1: You work in HR for a company that operates a factory manufacturing fiberglass. There are several hundred empl

Details on advanced accounting paperthis paper is intended

DETAILS ON ADVANCED ACCOUNTING PAPER This paper is intended for students to apply the theoretical knowledge around ac

Create a provider database and related reports and queries

Create a provider database and related reports and queries to capture contact information for potential PC component pro

Describe what you learned about the impact of economic

Describe what you learned about the impact of economic, social, and demographic trends affecting the US labor environmen