Final - Solutions

Procedures/Theory:
  1. F value=1495.84; Dep Mean=103.01903; INTERCEP=47.641; x=0.372
  2. Normality reasonable; no outliers and no distinct bias; homoscedasticity reasonable. Hence use the ANOVA p-value (i.e. Pr>F: 0.2293) which is not significant. Conclude that there is insufficient evidence to reject the null hypothesis of equal sub-population means. Also, the conclusion is not sensitive to the normality assumption (i.e. CHISQ p-value 0.1434).
  3. Remember that lower PRESS is better and assume that x1=1 indicates subpopulation 1, x2=1 indicates subpopulation 2 etc.
    1. Since 1000.10 is lowest, the model is: y=beta0+beta1(x1)+error where errors (for fixed x1) are assumed to be unbiased, homoscdastic and normally distributed.
    2. Since x1=1 for subpopulation 1 and 0 otherwise then mu1=beta0+beta1 and mu2=beta0 where mu2 is the combined mean of all other subpopulations.

SAS:

  1. Variables X, Y and Z exist:
    1. label X="Starting Salary" Y="Major" Z="GPA";
    2. title "Final - CSC423/324";
    3. proc means; var X Z;
      Note: Alternatively: proc univariate; var X Z;
    4. Add the 'normal' and 'plot' options to proc univariate.
  2. Eight errors: '123' not a valid dataset name; ';' missing after 123; 'MANUFTYPE' too long; MANUFCD and MANUFTYPE should be string; DATALINES missing; 'CLASS MANUFCD;' missing for PROC ANOVA; PROC missing for PRINT.