(21) 3. For n : 76 brands of breakfast cereals, calories per serving, sodium content (in mg), carbohydrate content (in g) and sugar content (in g) were measured. The summaries below include the correlation matrix and the multiple regression with calories as the response variable. Quantiles Correlation matrix calories sodium sugars carbo calories sodium sugars carbo Min. : 50 0 0.00 5.0 calories 1.0000 0.2992 0.5665 0.2576 1st Qu.:100 134 3.00 12.0 sodium 0.2992 1.0000 0.0589 0.2977 Median :110 180 7.00 14.5 sugars 0.5665 0.0589 1.0000 0.4712 Mean :107 162 7.03 14.8 carbo 0.2576 0.2977 0.4712 1.0000 3rd Qu.:110 212 11.00 17.0 Max. :160 320 15.00 23.0 Coefficients: Estimate Std. Error t value Pr(>|tl) (Intercept) 29.1384 7.2004 4.05 0.00013 sodium 0.0129 0.0172 0.75 0.45677 sugars 3.8957 0.3497 11.14