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

(i)

(ii)

From graphing calculator,

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:

(iv)

When .

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.

2013 A-level H1 Mathematics (8864) Suggested Solutions | The Culture[…] 2013 A-level H1 Mathematics (8864) Question 9 Suggested Solutions […]