Statisics a binomial experiment

Question

58% of Us adults have very little confidence in the newspaper you randomly selected from ten US adults. Find the probability that the number of US adults who have very little confidence in the newspaper is A exactly five B at least six and c less than four

Answer 1

Hi Chris,

As you mentioned this is a binomial distribution problem.

Probability of Success = 58%

Number of Trials = 10

A. P(x = exactly 5) = BinomialPDF(5,10,0.58) = 0.2162 , can be done using the BinomDist function in excel, the equation =BINOM.DIST(5,10,0.58,FALSE) will give you the same answer

B. P(x = at least 6) = 1 - BinomialCDF(5,10,0.58) = 1 - 0.4178 = 0.5822, can be done in excel using the following equation: =1-BINOM.DIST(5,10,0.58,TRUE) this gives the same answer. You can also find the probabilities individually by adding the P(x=6) + P(x=7) + P(x=8) + P(x=9) +P(x=10).

C. P(x < 4) = BinomialCDF(3,10,0.58) = 0.0712, done in excel using the following formula =BINOM.DIST(3,10,0.58,TRUE), or by adding the probabilities individually, P(x=0) + P(x=1) + P(x=2) + P(x=3).

Hope this helps!