Stats problem. who is bored

invader7

invader7

Active member
Over time, a student analyzes her ability to guess correctly after narrowing down mutiple choice answers in a 5-selection question (choices a through e). She discovers that if she narrows her answer set to 2 or 3 choices, her probability the right answer is 0.8, but if she still has 4 or 5 choices 70% of the time, What is the probability that she will answer a question correctly any time she must guess? Draw the tree diagram & justify your answer.
 
what? retype the question, work on your english.

I think youre saying if she has 2 or 3 choices her proabblity of getting it right is .8?

If she has 4 or 5 her probability is .7? What are the frequencies for having 2/3 or 4/5
 
Over time, a student analyzes her ability to guess correctly after narrowing down mutiple choice answers in a 5-selection question (choices a through e). She discovers that if she narrows her answer set to 2 or 3 choices, her probability the right answer is 0.8, but if she still has 4 or 5 choices her probability of choosing the right answer quickly decreases rapidly to .1 assuming that in general she can narrow her choices to 2 or 3 70% of the time, What is the probability that she will answer a question correctly any time she must guess? Draw the tree diagram & justify your answer.

correction. my bad and i was wrong
 
Haven't taken stat but what I know from tree diagrams should be something like 59%you have the original question as your starter point, first brach is eitehr 70% or 30% that she can narrow down the question,
Then from there, if she narrows it down to 2 or 3 and guesses, she has an 80% chance, so .7 x .8 = .56ANDif she can't narrow it down and guesses, she has a 10% chance of getting it right, so .3 x .1 = .03
therefore:.56 + .03 = .59 = 59%
Hope this makes sense / helps
 
makes sense to me, and is better than the answer i had. thanks man and plus karma. and if anyone else has a better attempt feel free to still post.
 
you think this is a bad question? This is word for word a question from one of my stats tests last semester

The random variable X= number of pieces of Reese.

a. 9

b. 1

c. 8

d. 10

e. none of the above

 
LOL%20KEIRA2.JPG
 
oh yeah, my bad. this is right. i mixed up the numbers thinking that the 70% one was for her not narrowing down her answers instead of actually narrowing down her answers. my mistake, thats what happens when i do it in my head i guess
 
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