The following data represent the number of calories per serving and the number of grams of sugar per serving for a random sample of high-fiber cereals.

(a) Draw a scatter diagram of the data treating calories as the explanatory variable. What type of relation appears to exist between calories and sugar content?
(b) Determine the correlation between calories and sugar content. Is there a linear relation between calories and sugar content?
(c) Suppose that we add Kellogg's All-Bran cereal, which has 80 calories and 6 grams of sugar per serving, to the data set. Redraw the scatter diagram and recompute the correlation between calories and sugar content. Is there a linear relation between calories and sugar content with All-Bran included in the data set? Is All-Bran an influential observation?
(d) Explain why it is necessary to show a scatter diagram with the correlation coefficient when claiming that a linear relation exists between two variables.

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Sugar, y Calories, r Calories, x Sugar, y 200 18 210 23 210 23 210 16 170 17 210 17 190 20 190 12 200 18 190 11 180 19 200 11