2012 A-level H2 Mathematics (9740) Paper 2 Question 9 Suggested Solutions

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

Firstly, the probability that a voter supports the Alliance party is a constant.
Secondly, each voter’s decision to vote for Alliance Party is independent of another voter’s decision.
Lastly, voters can only decide to vote or not vote for Alliance Party.

\mathrm{P}(A = 3) \mathrm{P}(A = 4) = 0.373

Since n is large, np = 16.5 > 5 ~\&~ nq = 13.5 > %, we can approximate A with a normal distribution.

Since n is large, np = 16.5 > 5, we cannot approximate A with a poisson distribution.

\mathrm{P}(A = 15) = 0.06864

{30 \choose 15} p^{15} (1-p)^{15} - 0.06864

[p(1-p)]^{15} = 4.42503 \times 10^{-10}

p(1-p) = 0.2379

p = 0.39 \text{~or~} 0.61

Since p \textless 0.5, \Rightarrow p = 0.39

KS Comments:

(i), writing two of the three will suffice since it is two marks.
(iv), it is necessary that we show that equation so students need to pay attention to their expansion of indices here. The formula applied here can be found in MF15 so students should take note.

Leave a Comment

Contact Us

CONTACT US We would love to hear from you. Contact us, or simply hit our personal page for more contact information

Not readable? Change text. captcha txt

Start typing and press Enter to search