## anonymous one year ago 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.

1. misty1212

HI!!

2. misty1212

binomial should work for this one

3. misty1212

what is the probability you get any one question right?

4. misty1212

if you do not know, say so and i can tell you hint, there are 4 possible answers, only one is right

5. anonymous

I really don't know..

6. misty1212

one is right, out of four ratio is $$\frac{1}{4}$$ i.e. the probability you get any one answer correct is $$\frac{1}{4}$$

7. misty1212

you also need the probability you get any one answer incorrect you know that?

8. anonymous

3/4?

9. triciaal

|dw:1438222812257:dw|

10. misty1212

yes it is $$\frac{3}{4}$$ for wrong answers

11. misty1212

now you want 3 out of 5, so 3 right, 2 wrong

12. misty1212

probabiliy of getting any one answer right is $$\frac{1}{4}$$ and you want 3 right so $$(\frac{1}{4})^3$$ also 2 wrong, so $$(\frac{3}{4})^2$$

13. misty1212

then then multiply by the number of ways to choose 3 out of 5 that is called "five choose three" sometimes written as $\_5C_3$ or more commonly $\binom{5}{3}$ and computed via $\binom{5}{3}=\frac{5\times 4}{2}$

14. misty1212

final answer is $10\times \left(\frac{1}{4}\right)^3\times \left(\frac{3}{4}\right)^2$ use a calculator

15. anonymous

.009765625?

16. anonymous

hello????/

17. anonymous

i don''t know i didn't do it hold on

18. anonymous