Marx: Lab9

Today just get the r, intercept and b (slope) out from the software programs. You should be able calculate and interpret the "r" today.

Table 9-1 shows the results based on a classic piece of small group research in which the size of groups (X) is related to the tendency of group members to perceive closeness  (Y).  Using the data in Table 5-1 do the problems by hand and by computer.  DUE: OCT 24 (beginning of class).

  Only new command needed is:

 Traditional SAS:                                                                   
Proc Reg Corr Simple;                                                          
Model dependent var = predictor var/P;                                
Run;

 SPSS:
Click>Analyze, then Correlate, then Bivariate. Move the variable over (make sure that the Pearson box under correlations is checked)--okay to run
 Click>Analyze, the Regression, then Linear-be sure to drag the dependent (Y) and Independent into the appropriate box--okay to run;

Enterprise (ignore)

Select Linear Regression (from Taskbar)
Drag dependent variable (y) and predictor (x) to appropriate slots.
 

Select Multivariate Correlation.
Drag Analysis variable (which is X or size here)
Drag correlated variable (which is Y or closeness)
 

All work must be done by hand and computer (traditional SAS and  SPSS)

Table 9-1

Perception of  Group Closeness (Y) by Size of Group (X), for Ten Groups

                                    X                                                                Y

                                                                                              Percent Perceiving
                         Group Size                                                    Group Closeness

                                    2                                                                      100
                                    2                                                                      65
                                    3                                                                      30
                                    3                                                                      40
                                    4                                                                      25
                                    4                                                                        8
                                    5                                                                        2
                                    5                                                                      15
                                    6                                                                        0
                                    7                                                                      10

1)         Compute the correlation (r) between x and y.

           *  B)  Put the results in a sentence that describes the relationship between group size and
                   member’s perceptions.

2)         Compute the slope (b).

                 B)  Put the result in a sentence that describes the relationship between group size and
                        member’s perceptions (interprete slope)

3)            Compute the intercept (a)

                     B)        Write out the line equation as a whole.

4)         Compute the coefficient of determination (r square).

                  B)   Put the result in a sentence that describes the relationship between group size and
                         member’s perceptions (interprete coefficient of determination)