Probablity Reasoning SAC

[Aqualim]

Hey folks,

I have a probability reasoning SAC this thursday and there will be questions asking me to find the correct answer out of 5 possible multiple choice answers and then I will be asked to change the question to get one or all of the other possibilities. I generally don't have too much trouble getting the correct answer, but what is the best way I could find the incorrect answers?

I've noticed you can't just simply make one of the values x and then solve with probability e.g. solve(BinomCdf(10,1/2,x,10)=0.99923,x)

Any other ways of going about it, instead of just typing in random numbers and hoping for the best?

[sajib_mostofa]

Would you be able to provide any info as to what sort of Q's might be on there?

[Aqualim]

Something like;

A fair coin is tossed ten times, and the number of heads is recorded each toss. Find the probability of achieving equal to or more than eight heads out of the ten tosses.

a) 0.0039
b) 0.055
c) 0.989
d) 0.994
e) 0.00098

So it will ask me to show working for how I got the correct answer and then tell me how I could re-word the question to get all of the incorrect answers

[Jdog]

well with these kinda of problems you can create a binomial distribution table on your calculator, and check the values to which each answer corresponds.

This sac sounds very interesting, mind you I wouldn't want to do one of the sort,

[sajib_mostofa]

Hmm I have to admit, you have a very tough SAC on your hands (not to scare you or anything). I really cant think of any other way than using some experimentation or the binomial table that JDog suggested.

[Jdog]

with the nspire it works out really well, just go to te spreadsheet tab and then type in the binomail stuff

[8039]

Something like;

A fair coin is tossed ten times, and the number of heads is recorded each toss. Find the probability of achieving equal to or more than eight heads out of the ten tosses.

a) 0.0039
b) 0.055
c) 0.989
d) 0.994
e) 0.00098

So it will ask me to show working for how I got the correct answer and then tell me how I could re-word the question to get all of the incorrect answers

Is the answer b? that's what I got

[8039]

So the n= 10, p= 1/2 and finding for Pr(X greater than or equal to

Using bionmCDF I typed in (10,0.5,8,10) and got 0.0546