Look at the scatterplot below. does it demonstrate a positive or

Data File 4/Statistics in Educational Research (***** Correct Solution delay march by march Calculation *****)


Data File 4


Show all your composition


Chapter Seven



Problem 1)  Look at the scatterplot beneath.  Does it present a enacted or denying interdependence?  Why? Are there any outliers?  What are they? 




Problem 2)  Look at the scatterplot beneath.  Does it present a enacted or denying interdependence?  Why? Are there any outliers?  What are they? 





Problem 3)  The forthcoming axioms succeed from your compass, problem 26 on page 298.  Here is the axioms:



                        Mean daily calories                             Infant Mortality Rate (per 1,000 births)


                        1523                                                    154     


                        3495                                                    6


                        1941                                                    114


                        2678                                                    24


                        1610                                                    107


3443                                                    6


1640                                                    153


3362                                                    7



3429                                                    44


2671                                                    7


  1. For the over axioms build a scatterplot using SPSS or Excel (Follow instructions on page 324 of your textbook).  What does the scatterplot profession?  Can you detailize a form of similarity? Are there any outliers that you can see?

  2. Using the identical axioms influence a interdependence separation using SPSS or Excel.  What is the interdependence coefficient?  Is it a solid, limited or purposeless interdependence?  Is the interdependence momentous or not?  If it is what does that medium?   


    Problem 4)


    Bill is doing a design for you in the marketing province.  In influenceing his separation touching consumer demeanor and a new composition that has succeed out, he tells you the interdependence betwixt these two changeables is 1.09.  What is your defense to this separation?


    Problem 5)


    Judy has influenceed an separation for her overseer.  The development she obtained was a interdependence coefficient that was denying 0.86.  Judy is involved by this calculate and feels that consequently it is denying and not enacted, is mediums that it is bad.  You are her overseer.  How would you whitewash this development for Judy touching the mediuming of the interdependence?


    Problem 6)

               Explain the declaration, “interdependence does not recommend potentiality.”


    Problem 7)    

                 Using the best-fit cord beneath for vaticination, solution the forthcoming questions:


    1. What would you prognosticate the appraisement of Composition X in bulk of 150 to be (approximately)?

    2. What would you prognosticate the appraisement of Composition X in bulk of 100 to be (approximately)?




       Problem 8)


      You are assiduous in furnishing out if a student’s ACT jaw is a amiable prognosticateor of his or her ultimate garden progression purpose middle (GPA).  You feel obtained the forthcoming axioms and are going to influence a retirement separation.  Follow the instructions on page 324 of your textcompass to influence this separation:

      ACT    GPA

       22.0     3.0

      32.0     3.78

      33.0     3.68

      21.0     2.94

      27.0     3.38

      25.0     3.21


      30.0     3.65


      1. What is the R?  What form of similarity does it designate (strong/weak; enacted/negative)?

      2. Go to the coefficients readout.  The immutable is the stop.  Under that is the ACT and that is the swell.  Using the rectilinear cord formula of Y = mx + b, which you conquer furnish on page 313, you conquer now prognosticate some forthcoming GPA jaws:  In the formula (m) is the swell; (x) is the changeable that you are looking to use as a prognosticateor; and (b) is the stop.  Predict GPA from the forthcoming ACT jaws using the retirement equation/rectilinear cord formula (profession all your composition):


        1. 20

        2. 25

                     3. 34




Chapter Eight


Show all your composition


Problem 1)


A illustration of nine students is clarified from unarranged the students vestibule a  detail exam.  The nine students were asked how considerable occasion they had gone-by examineing for the exam and the defenses (in hours) were as follows:


            18, 7, 10, 13 12, 16, 5, 20, 21

Estimate the medium examine occasion of all students vestibule the exam. Round your solution to the rectilinear tenth of an hour, if compulsory.


Problem 2)


Scores on a detail trial feel a medium of 64.6.  The distribution of illustration mediums for illustrations of bigness 100 is typical delay a medium of 64.6 and a rule hiatus of 1.9.  Suppose you seize a illustration of bigness 100 of trial jaws and furnish that the medium is 63.  What is the z-jaw identical to this illustration medium?


Problem 3)


There are 349 teachers at a garden.  Among a illustration of 110 teachers from this garden, 66 feel doctorates.  Based on this illustration, affect the calculate of teachers at this garden delayout doctorates.


Problem 4)


Sample bigness = 400; illustration medium = 44; illustration rule hiatus = 16.  What is the lip of blunder? 


Problem 5)


A illustration of 64 statistics students at a balance garden had a medium mathematics ACT jaw of 28 delay a rule hiatus of 4. Estimate the medium mathematics ACT jaw for all statistics students at this garden.  Give the 95% reliance cessation. 


Problem 6)


A government scan influenceed to affect the medium appraisement of houses in a metropolitan area is contrived to feel a lip of blunder of $10,000.  Pilot studies recommend that the population rule hiatus is $70,000.  Estimate the partiality illustration bigness needed to affect the population medium delay the orderly prevention. 


Problem 7)


A researcher wishes to affect the symmetry of garden students who finesse on exams.  A poll of 490 garden students professioned that 33% of them had, or contrived to, finesse on examinations.  Find the lip of blunder for the 95% reliance cessation. 



Data File 4 Statistics in Educational Research