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plz help ty In a study by Peter D Hart Research Associates or the Nasdaq Stock M

ID: 3056299 • Letter: P

Question

plz help ty

In a study by Peter D Hart Research Associates or the Nasdaq Stock Market, t as determined that 20% o a stock vestors are et d pe pie In additon, 40% all us adults est in mutual funds. uppose a random sample of 5 st kin estos sta en a. What is the probability that exactly seven are retired people? b. What is the prabability that 10 or more are retired people? c. How many retired people would you expect to find in a random sample of 25 stock Investors? d. Suppose a random sample of 20 U.S. adults is taken. What is the probability that exactly eight adults invested in mutual funds? e. Suppose a random sample of 20 U.5, adults is taken. What is the probabillity that fewer than six adults invested in mutual funds? . Suppose a random sample af 20 U.S. adults is taken. What is the probab lity that none of the adults invested in mutual funds? Suppose a ndom sam of 20 u.s find in g. Suppose a random sample of 20 U.S, adults is taken, what is the probability that 12 or more adults invested in mutual funds? adulb inewested in d 0. Suppose h. For parts e-q, what exact number of adults would produce the highest probability? How does this compare to the expected number? (Round your answers to decimal places when calculating using Table A2.) (Round your answer to 7 decimal places ound your answer (Round your answer to 0 decimal places.)

Explanation / Answer

f) P(x=0)

n=20

p=0.40

q=1-p =1-0.4 =0.6

P(x=0) =nCr p^r q^(n-r)

            =20C0 (0.4)^0 (0.6)^(20-0)

            =1 * 1 * 0.0000365

            =0.000 (rounded to 3 decimal places)

g) P(x>=12)

n=20

p=0.40

q=1-p =1-0.4 =0.6

P(x>=12) =1-P(x<20)

            =1-0.943473

            =0.057