This graph plots the residuals versus the fitted values. The residuals should be scattered randomly about zero. Use this plot to look for the following:

Based on the plot for strength, the residuals do no appear to be randomly scattered about zero. The residuals for the fitted strength values greater than 112.5 seem to have larger variances. To verify this analytically, the equal variance assumption was tested using Stat > ANOVA > Test for Equal Variances. The test results indicate insufficient evidence of unequal variance. The variation shown in the plot may be due to random fluctuations.

Based on the plot for elasticity, the residuals do no appear to be randomly scattered about zero. The residuals for the fitted elasticity values less than 84 have larger variances. To verify this analytically, the equal variance assumption was tested using Stat > ANOVA > Test for Equal Variances. The test results indicate that insufficient evidence of unequal variance. The variation shown in the plot may be due to random fluctuations.