Question

Solve by simulating the problem.
 
You have a 5-question multiple-choice test. Each question has four choices. You don’t know any of the answers. What is the experimental probability that you will guess exactly three out of five questions correctly? Type your answer below using complete sentences.

Answer 1

@nader1

Answer 2

I'll be right back! AFK

Answer 3

you want answer or i wait you?

Answer 4

wait

Answer 5

kk

Answer 6

@nader1 ok im back

Answer 7

to get the experimental probability, you have to run the experiment.

Answer 8

ok how do i do that?

Answer 9

this is a binomial situation

Answer 10

Consider the probability of success for each trial, the number of trials, the number of successes sought, and the number of combinations of getting that many successes.

Answer 11

1 in 4?

Answer 12

exactly 3 right out of 5 means 3 right, 2 wrong and (5/2) ways to do it

Answer 13

Number of ways to get 3 out of 5 = 5C3 = 5C2 = 10, so the 10 in right.

Answer 14

so its 5/2 ways to do it

Answer 15

... *is right.

3 successes = (.25)^3 with a 25% chance of getting any question correct at random.
2 failures = (.75)^2 for similar reasons as above.

Answer 16

See http://stattrek.com/probability-distributions/binomial.aspx?Tutorial=Stat
for derivation of the binomial formula.

Answer 17

I think you have everything you need; just multiply it all together.

Answer 18

oh i see

Answer 19

There are ten ways to get 3 out of 5. (use combinations formula 5choose3)
To get 3 successes with a 25% chance each, that's 0.25 × 0.25 × 0.25 = (0.25)^3
To also get the 2 failures with a 75% chance: 0.75 × 0.75 = (0.75)^2

Altogether, the probability is 10 × (0.25)^3 ×(0.75)^2.

Answer 20

so thats the probability...thanks

Answer 21

this one was reallly confusing..:)

Answer 22

Makes sense to me. 10 ways to have 3 successes and 2 failures multiplied by the probability of having 3 successes multiplied by the probability of having 2 failures.

See also http://stattrek.com/probability/probability-rules.aspx?Tutorial=Stat

Answer 23

Follow those links to that website I posted and study until you understand why the probability is computed that way

Answer 24

good teaching :P?

Answer 25

ok thanks nader brb

Answer 26

you welcome :)

Answer 27

dont forget medal ^^

Answer 28

thanks

Answer 29

anytime :) i hope i help you good