Question

Hello, I know the answer is D. Can someone tell me the procedure used to get the answer?

Find the indicated probability. Round to three decimal places. A test consists of 10 true/false questions. To pass the test a student must answer at least 6 questions correctly. If a student guesses on each question, what is the probability that the student will pass the test?

A. 0.828

B. 0.172

C. 0.205

D. 0.377

Answer 1

do you have a calculator like a TI-83 or TI-84?

Answer 2

Yes

Answer 3

TI-84 Plus

Answer 4

A test consists of 10 true/false questions.

To pass the test a student must answer at least 6 questions correctly.

If a student guesses on each question, what is the probability that the student will pass the test?

P(x=6) + P(x=7) + P(x=8) + P(x=9) + P(x=10)

is at least 6 right

Answer 5

open your distribution menu; 2nd vars i beleive, and pick binomCDF

Answer 6

Okay, I have opened binomcdf

Answer 7

or since P(t) = .5 and P(f) = .5 the binomial thrm get us:
\[\sum_{n=6}^{10}\binom{10}{n}(.5)^{n}(.5)^{10-n}\]
\[\sum_{n=6}^{10}\binom{10}{n}(.5)^{10}\]
\[(.5)^{10}\sum_{n=6}^{10}\binom{10}{n}\]
should work as well

Answer 8

binomCDF(n,p,x) are the inputs

n=10, p=.5, x=5 why?

binom counts up from x=0 to x=k

we want from (k+1) to 10 soo

1 - binom(10,.5, 5) gets us there