All solutions here are SUGGESTED. Mr. Teng will hold no liability for any errors. Comments are entirely personal opinions.

(i)

Graph for 9(i)
Graph for 9(i)

(ii)
From graphing calculator, r = 0.903

r-value is close to 1 which suggest a strong positive correlation between the variables x and y.

(iii)
From graphing calculator, required regression line: y = 4.46x + 87.43

(iv)
When x = 13.2, y = 146.

Since r is close to 1, and we used the regression line of y on x to estimate y given an x within the range of data, the estimate will be reliable.

KS Comments

Very standard. Some students made mistake while keying values into the GC unfortunately.

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