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

Question to qualify for security officers training recruits

Question: To qualify for security officers training, recruits are tested for stress tolerance. The scores are normally distributed with a mean of 62 and a standard deviation of 8. If only the top 15% of recruits are sele ...

A population of lawnmowers life expectancy is described

A population of lawnmowers' life expectancy is described with a Weibull distribution, where α=1 and β=15. Determine 1× (once) and 2× (twice) the expected mean lifes for the population, as well as their corresponding cumu ...

Lucerne earns a gross income of 5500 per month and applies

Lucerne earns a gross income of $5,500 per month and applies for a mortgage with a monthly PITI of $1,244. Lucerne has other financial obligations totaling $829 per month. (Use the ratio guidelines from your text) What t ...

Assignmentsuppose that there are two candidates ie jones

Assignment Suppose that there are two candidates (i.e., Jones and Johns) in the upcoming presidential election. Sara notes that she has discussed the presidential election candidates with 15 friends, and 10 said that the ...

One thousand people are enrolled in a 10 year cohort study

One thousand people are enrolled in a 10 year cohort study. At the start of the study, 100 have diagnosed CVD. Over the course of the study, 80 people who were free of CVD at baseline develop CVD. What is the cumulative ...

Historically 25 of all students taking an statistics course

Historically 25% of all students taking an statistics course have failed (i.e. receive a grade below C). Professor Han thinks that she has a better method of teacher statistics to business students. She is given a random ...

A professor has learned that four students in her class of

A professor has learned that four students in her class of 18 will cheat on the exam. She decides to focus her attention on seven randomly chosen students during the exam. a. What is the probability that she finds at lea ...

Question at the first state bank the average savings

Question: At the first state bank the average savings account balance in 2004 was $1300 with a standard deviation of $80. A random sample of 45 savings account balances for 2005 yielded a mean of $1350. At the alpha=01 s ...

Question 1use this extract taken from the article goji

Question 1: Use this extract taken from the article, "Goji berries prevent macular degeneration," (appeared in Healthy Foods, Healthy Bodies on January 21, 2016) to answer the questions that follow: Goji berries (Lycium ...

Use the given degree of confidence and sample data to

Use the given degree of confidence and sample data to construct a confidence interval for the population proportion p. Round to three decimal places. n=74, x=12; 95% confidence.

  • 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

WalMart Identification of theory and critical discussion

Drawing on the prescribed text and/or relevant academic literature, produce a paper which discusses the nature of group

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