Question

Based on a​ poll, among adults who regret getting​ tattoos, 28​% say that they were too young when they got their tattoos. Assume that four adults who regret getting tattoos are randomly​ selected, and find the indicated probability. Complete parts​ (a) through​ (d) below.

a. Find the probability that none of the selected adults say that they were too young to get tattoos.

b. Find the probability that exactly one of the selected adults says that he or she was too young to get tattoos.

c. Find the probability that the number of selected adults saying they were too young is 0 or 1.

d. If we randomly select four ​adults, is 1 a significantly low number who say that they were too young to get​ tattoos

No/Yes, because the probability that more than 1/at most 1/less than 1/at least 1/exactly 1 of the selected adults say that they were too young is less than/equal to/greater than 0.05.

Answer 1

here this is binomial with parameter n=4 and p=0.28

a)

probability =

P(X=0)=

(nCx)px(1−p)(n-x)    =

0.2687

b)

probability =

P(X=1)=

(nCx)px(1−p)(n-x)    =

0.4180

c)

probability =

P(X<=1)=

∑x=0x     (nCx)px(1−p)(n-x)    =

0.6868

d)

No , because the probability that  at most 1  of the selected adults say that they were too young is  greater than 0.05.