Question

58​% of U.S. adults have very little confidence in newspapers. You randomly select 10 U.S. adults. Find the probability that the number of U.S. adults who have very little confidence in newspapers is ​ (a) exactly​ five, (b) at least​ six, and​ (c) less than four.

a) ​P(5)=
(b) ​P(x​≥6)=
​(c) ​P(x​<4)=

Answer 1

.216165788

.582225057

.417774943

Explanation:

We need to use a binomial distribution here

A.

10C5*.58⁵*(1-.58)⁵= .216165788

B.

I honestly think the fastest way to solve this is adding the probabiblity of exactly 6,7,8,9,10

which means we write

10C6*.58⁶*(1-.58)⁴+10C7*.58⁷*(1-.58)³+10C8*.58⁸*(1-.58)²+10C9*.58⁹*(1-.58)+10C10*.58¹⁰= .582225057

C.

To solve this just take the compliment of answer B

1-.582225057= .417774943