u/Fabulous-String2858

1. a) E(X)= 3
   b) E(X^2)= 11

2. b) P(3 wins) = 0.162
   c) P(2 wins) = 0.648

3. a) width: 1.42cm height: 14.8cm
   b) median: 24.3 (for n+1/2)
   c) sd: 9.18cm

4. a) E(2X +4) = 10.44
   b) Var(2X+4) = 7.086
   c) Var (4 -2X) = 7.086

5. a) sum of y^2 = 39875
   b) Sxy= 1677.5
   c) r= 0.962

6. a) P(C) = x + 0.2
   b) P(C|D) = 0.2/ (y +0.2)
   c) P(CuD) = x + y + 0.2
   d) x=0.52, y=0.04

7. a) p= 16.24 + 0.832t
   b) student A= 68. student B= 33 (i rounded)

8. a) i got wrong because i didnt realise that 9 was variance and not standard deviation 😞 but i got P(X<440) = 0.3707, P(441.5<X<447.5) = 0.644. k=20.88
   b) mean = 343, standard deviation 2.38

written questions: r doesnt change, negative skew, estimate A is more reliable, every increase in 1 mark in the theory test caused an increase of 0.832 in practical test

how many marks was part a question 8?

these are my answers idk if theyre correct or not:

1. remainder:2 quotient: 2x^2 -3x -1.
2. pi, 16.0
3. arrithmetic: -15, geometric: 12. U3= 39
4. area: 2.148, volume: 12.12.
5. i -1.86, ii a) 3+ a b) 1/2 -2a
6. 1 + 25/8 x + 1125/256 x^2 . k= 1024. estimate= 33/16
7. centre: (4,-6) radius: 5 area: 25/2 pi + 8
8. x= 84.57, dy2/d2x = 0.06587... so minimum.

im missing a question but im not sure which one