Hi everyone,

These are just the answers. I'll to post worked solutions later. Sorry for the delay. There's now a rule which says that teachers can get the papers 2 hours after starting. Last year it was 30 minutes.

Anyway ... for the record ...

1. A

2. D

3. B

4. C

5. B

6. B

7. D

8. C

9. C

10. C

11. A

12. B

13. D

14. A

15. A

16. C

17. D

18. D

19. B

20. C

21. B

22. B

(a) 4ab/3

(b) (i) 19*C

(ii) February

(iii) May, June, July, August, September

(c) (i) Systematic sample, something like every 5th student in order on the roll. Can also be a straight random sample, like names out of a hat. Can also be a stratified sample based on number of students in each year group, then a systematic or random sample from each year group.

(ii) Mean is 7.275 hours per week (using class centres). Mean class is 5-9 hours per week.

(d) (i) $6

(ii) 4 kg or 7 kg

(iii) Weights more that 4 kg, up to and including 6 kg, and weights more than 7 kg.

(iv) $1.50 per kg

(a) Vertical axis does not start at 0, pictures change in three dimensions instead of just one.

(b) (i) 70*

(ii) 109 cm

(c) Lovely box plot, Min = 140, Q1 = 145, Median = 150, Q3 = 170, Max = 190

(d) (i) 567 L

(ii) 30 cm

(a) (i) 6

(ii) 1/3

(iii) 2/3

(b) (i) 29 days

(ii) $8.61

(c) (i) 1/60

(ii) 1/5370

(d) Martha's effective interest rate is 6.76% p.a. so she gets the better deal.

(a) (i) Lovely diagram

(ii) 53 m

(b) (i) Lovely net - probably best is to have four lots of a triangle on top of a rectangle next to each other across the page.

(ii) 252 m

(c) (i) 98

(ii) 43/100

(iii) 28

(d) 17 h 30 min

(a) (i) $130 000 over 30 years

(ii) $45964.80

(b) (i) y-intercept exists when height = 0 cm, but this will never occur. No person ever has a height of 0 cm.

(ii) George's feet should be 3 cm longer than Harry's

(iii) For this data, correlation coefficient should be positive rather than negative. Correlation coefficients only range from -1 to 1 so r = -1.2 is not possible.

(c) (i) $24000

(ii) $7593.75

(iii) Graph - Straight line from $30000 to $24000 after 3 years, then curve down to $7593.75 after 7 years

(a) (i) 4 combinations: 1 x $2, 1 x 50c; 2 x $1, 1 x 50c; 1 x $1, 3 x 50c; 5 x 50c

(ii) 6/55

(iii) $(2

(b) (i) $12

(ii) 3500 vehicles, daily income $17 500

(iii)

(iv) Anne's statement is incorrect. Maximum daily income is $18 000 when the toll is set at $6 per vehicle.

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Worked solutions attached ... finally!

These are just the answers. I'll to post worked solutions later. Sorry for the delay. There's now a rule which says that teachers can get the papers 2 hours after starting. Last year it was 30 minutes.

Anyway ... for the record ...

**Section I**1. A

2. D

3. B

4. C

5. B

6. B

7. D

8. C

9. C

10. C

11. A

12. B

13. D

14. A

15. A

16. C

17. D

18. D

19. B

20. C

21. B

22. B

**Section II****Question 23**(a) 4ab/3

(b) (i) 19*C

(ii) February

(iii) May, June, July, August, September

(c) (i) Systematic sample, something like every 5th student in order on the roll. Can also be a straight random sample, like names out of a hat. Can also be a stratified sample based on number of students in each year group, then a systematic or random sample from each year group.

(ii) Mean is 7.275 hours per week (using class centres). Mean class is 5-9 hours per week.

(d) (i) $6

(ii) 4 kg or 7 kg

(iii) Weights more that 4 kg, up to and including 6 kg, and weights more than 7 kg.

(iv) $1.50 per kg

**Question 24**(a) Vertical axis does not start at 0, pictures change in three dimensions instead of just one.

(b) (i) 70*

(ii) 109 cm

(c) Lovely box plot, Min = 140, Q1 = 145, Median = 150, Q3 = 170, Max = 190

(d) (i) 567 L

(ii) 30 cm

**Question 25**(a) (i) 6

(ii) 1/3

(iii) 2/3

(b) (i) 29 days

(ii) $8.61

(c) (i) 1/60

(ii) 1/5370

(d) Martha's effective interest rate is 6.76% p.a. so she gets the better deal.

**Question 26**(a) (i) Lovely diagram

(ii) 53 m

(b) (i) Lovely net - probably best is to have four lots of a triangle on top of a rectangle next to each other across the page.

(ii) 252 m

^{2}(c) (i) 98

(ii) 43/100

(iii) 28

(d) 17 h 30 min

**Question 27**(a) (i) $130 000 over 30 years

(ii) $45964.80

(b) (i) y-intercept exists when height = 0 cm, but this will never occur. No person ever has a height of 0 cm.

(ii) George's feet should be 3 cm longer than Harry's

(iii) For this data, correlation coefficient should be positive rather than negative. Correlation coefficients only range from -1 to 1 so r = -1.2 is not possible.

(c) (i) $24000

(ii) $7593.75

(iii) Graph - Straight line from $30000 to $24000 after 3 years, then curve down to $7593.75 after 7 years

**Question 28**(a) (i) 4 combinations: 1 x $2, 1 x 50c; 2 x $1, 1 x 50c; 1 x $1, 3 x 50c; 5 x 50c

(ii) 6/55

(iii) $(2

*x*+*y*+ 0.5*z*)(b) (i) $12

(ii) 3500 vehicles, daily income $17 500

(iii)

*v*= 6000 – 500*d*, or*d*= 12 – (*v*/500)(iv) Anne's statement is incorrect. Maximum daily income is $18 000 when the toll is set at $6 per vehicle.

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Worked solutions attached ... finally!

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