Statistic questions part II

can someone help me with these questions? 1) recent history has shown that the movements of more than 3% in the Dow Jones industrial average ocur in 2% of the trading days. What is the probability that within the next 30 trading days there will be one or more days in which the average will more more than 3%? a) 0.4545 b)0.2876 c)0.1524 d)0.0836 2)a doctor knows that about 20% of the population will have an adverse reaction to a certain type of medicine. the doctor prescribes the medicine for 20 patients. find the probability that the number of patient who suffer an adverse reaction in the following: a) less than five b)more than two c) exactly three 3)consider choosing a five-card poker hand from a standard deck of 52 playing cards. what is the probability of having four aces? 4) the gambler introduced at the start of the chapter, the chevalier de mere, was particularly interested in the event that he could throw at least 1 six in 4 rolls of a die. what is the probability of that? my understanding for this question is (1/6)^4, but the answer does not seem like this, anything i missed? Please provided the answer with a brief explanation, i will definately appreciate for that… Thanks,

  1. 1 - prob(less than 3% for 30days) = 1 - (1-0.02)^30 = 1 - 0.5454 = 0.4545 4) my guess would be (1/6)*4 = 2/3 Hope that helps :slight_smile:
  1. Pain in the butt because you have to use binomial. P(less than 5) = P(0)+…+P(4) = 0.8^20+20*0.8^19*0.2^18+20 C 2 * 0.8^18 *0.2^2 +[] + [] = I dunno same for b, c. 3) # hands with 4 aces/# possible hands = 48/(52 C 5) 4) P(at least 1 six) = 1 - P(0 6’s) = 1 - (5/6)^4 (1/6)^4 = P(exactly 1 six)

gingerduck you look again like someone who is doing a statistics course somewhere, having trouble with your assignments and asking for help out here. While that might be ok, at all other times, given the one month left to the exam, I would recommend you go hit the books, and stop posting out here. Your messages are NOISE out here, on this site, where folks are seriously trying to prepare for a really tough examination. CP

for 4) Prob of atleast 1 six = 1 - Probability of no six = 1 - (5/6)^4 = 1 - (0.833)^4 = 1 - 0.48225 = 0.5177

JoeyDVivre Wrote: ------------------------------------------------------- > 2) Pain in the butt because you have to use > binomial. P(less than 5) = P(0)+…+P(4) = > 0.8^20+20*0.8^19*0.2^18+20 C 2 * 0.8^18 *0.2^2 +[] > + [] = I dunno > > same for b, c. > > 3) # hands with 4 aces/# possible hands = 48/(52 C > 5) > 4) P(at least 1 six) = 1 - P(0 6’s) = 1 - (5/6)^4 > > (1/6)^4 = P(exactly 1 six) Just curious (1/6)^4 = P(all 4 six) or P(exactly 1 six) ???

thunderanalyst Wrote: ------------------------------------------------------- > JoeyDVivre Wrote: > -------------------------------------------------- > ----- > > 2) Pain in the butt because you have to use > > binomial. P(less than 5) = P(0)+…+P(4) = > > 0.8^20+20*0.8^19*0.2^18+20 C 2 * 0.8^18 *0.2^2 > +[] > > + [] = I dunno > > > > same for b, c. > > > > 3) # hands with 4 aces/# possible hands = 48/(52 > C > > 5) > > 4) P(at least 1 six) = 1 - P(0 6’s) = 1 - > (5/6)^4 > > > > (1/6)^4 = P(exactly 1 six) > Just curious (1/6)^4 = P(all 4 six) or P(exactly 1 > six) ??? P(all 4 six). Did I right that?

cpk123, I dont know how come you have this thought but i am doing CFA exam in june, the reason that i cant understand stats coz i only took one paper in stats, is it clear for ur question? thanks,

To CP the reason i asking the stats questions coz i only took one stat paper before at uni, so i think it is clear for ur questions. And i am doing the TOUGH exam in june as u think. i know u r stressful rite now, but dun put ur anger to others. thanks, JoeyDVivre Wrote: ------------------------------------------------------- > 2) Pain in the butt because you have to use > binomial. P(less than 5) = P(0)+…+P(4) = > 0.8^20+20*0.8^19*0.2^18+20 C 2 * 0.8^18 *0.2^2 +[] > + [] = I dunno > > same for b, c. > > 3) # hands with 4 aces/# possible hands = 48/(52 C > 5) > 4) P(at least 1 six) = 1 - P(0 6’s) = 1 - (5/6)^4 > > (1/6)^4 = P(exactly 1 six)

If you are taking the CFA exam that is fine. There have been instances in the past, where lots of questions like this in the areas of Stats and Finance had been asked, and we were all merrily answering the questions, only to later find that the person asking the questions was a Univ. student, trying to get his homework done. That was the reason I made that statement above. It was not in anger, it was more asking you to wait for a better time, in case you were not preparing for the exam in close to a month’s time. Sorry about any misunderstanding caused.

Its ok, i will spend more time before i post next time, cheers, cpk123 Wrote: ------------------------------------------------------- > If you are taking the CFA exam that is fine. There > have been instances in the past, where lots of > questions like this in the areas of Stats and > Finance had been asked, and we were all merrily > answering the questions, only to later find that > the person asking the questions was a Univ. > student, trying to get his homework done. That was > the reason I made that statement above. It was not > in anger, it was more asking you to wait for a > better time, in case you were not preparing for > the exam in close to a month’s time. Sorry about > any misunderstanding caused.