Help required

A

Andrew Dimock

New member
Joined
Jan 10, 2022
Messages
3
Hi,

I am wanting to know the probability or chance of losing 20 trials in a row. 10 trials where I have a 80% chance of losing and 10 trails I have a 75% chance of losing.

Can you someone help me out please.

Thanks,
Andrew
 
Andrew Dimock said:
Hi,

I am wanting to know the probability or chance of losing 20 trials in a row. 10 trials where I have a 80% chance of losing and 10 trails I have a 75% chance of losing.

Can you someone help me out please.

Thanks,
Andrew
Click to expand...
Please show us what you have tried and exactly where you are stuck.

Please follow the rules of posting in this forum, as enunciated at:


Please share your work/thoughts about this problem.
 
I believe the answer might be 0.8^10 * 0.75^10 = ?

Which would mean 1 chance in about 165 I lost all 20 trials but this does not seem right to me?
 
Last edited by a moderator:
Okay maybe I didn't frame the problem properly. There are 20 individual trials, 10 of the trials I have a 20% chance of winning each individual one, and 10 of these trails I have a 25% chance of winning each individual one I am trying to calculate the probability of not winning any of the 20 trials.
 
Andrew Dimock said:
I believe the answer might be 0.8^10 * 0.75^10 = ?

Which would mean 1 chance in about 165 I lost all 20 trials but this does not seem right to me?
Click to expand...
How do you go from 0.8^10 * 0.75^10 to 1 in 165? You do realize that 0.8^10 * 0.75^10 < 1/165?
 
There is a reason why we ask that students give the exercise completely and exactly. A major issue that students often have is that they do not understand the problem because they still do not what information in the problem is relevant. Did the word “independent“ appear in the problem?
 
Jeff,
Do you think that the problem saying10 trials where I have a 80% chance of losing and 10 trails I have a 75% chance of losing would imply independent? If not, then why? (maybe I am missing something along with missing brain cells).
 
Hi jomo

My point here is that the OP has already said that he may not have framed the question correctly. That is an issue we can avoid if we are given the problem rather than having the student paraphrase it.

In all probability, the problem is asking about independent trials, but the differing probabilities in the first ten trials and second 10 trials make me at least wonder if there is some complexity that the OP has not recognized.

In any case, the student has made some progress. Under a reasonable interpretation of the student’s paraphrase, [imath]0.8^{10} * 0.75^{10}[/imath] is a useful number to calculate. Of course it is not the answer, and we need to calculate it correctly, but before we start helping the student see how a reasonable start went off the rails, I’d like to be sure I know what the actual problem is. And the student needs to learn to look for words like “independent.”
 
You must log in or register to reply here.
Top