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 ...
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 i dont noe bout this one, but rnt we meant 2 make the denominators the same, which will give = 3a6^3/3bw X 4w^2/3bw = 12ab^3w^2 ??? because denominator cancels out since theyr the same...
(b) (i) 19*C
(ii) February
(iii) August its asking in monthS = so its from may to september
(c) (i) Systematic sample, something like every 5th student in order on the roll. it can also b stratified
(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. also, scale of boxes are inacccurate = creates bias
(b) (i) 71* its 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 this isnt correct. d answer is 15cm... y did u X2? the trough is only d cm long... thats it
Question 25
(a) (i) 6
(ii) 1/3
(iii) 2/3
(b) (i) 28 days
(ii) $8.61
(c) (i) 1/60
(ii) 1/5370
(d) Martha's effective interest rate is 6.36%p.a. so Paul gets the better deal. i actually put them all into an annuity formula (with the same principal) and martha's one was higher, and i also double checked...???
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 m2
(c) (i) 98
(ii) 43/100 ??....its 74/200 = 37/100
(iii) 28
(d) 17 h 30 min
Question 27
(a) (i) $130 000 over 30 years .. also incorrect... max is $80 000 over 10 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 50¢; 2 x $1, 1 x 50¢; 1 x $1, 3 x 50¢; 5 x 50¢
(ii) 6/55
(iii) $(2x + y + 0.5z)
(b) (i) $12
(ii) $17 500 which is 3500 vehicles
(iii) v = 6000 – 500d
(iv) Anne's statement is incorrect. Maximum daily income is $18 000 when the toll is set at $6 per vehicle.
