Question

based on a poll, among adults who regret getting tattoos, 14% say that they were too young when they got their tattoos. assume that ten 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.
0.2213 (round to four decimal places as needed.)
b. find the probability that exactly one of the selected adults says that he or she was too young to get tattoos.
0.3603 (round to four decimal places as needed.)
c. find the probability that the number of selected adults saying they were too young is 0 or 1.
0.5816 (round to four decimal places as needed.)
d. if we randomly select ten adults, is 1 a significantly low number who say that they were too young to get tattoos?
because the probability that of the selected adults say that they were too young is 0.05
yes
no

Explanation:

Step1: Identify probability formula

This is a binomial - probability problem. The binomial probability formula is $P(X = k)=C(n,k)\times p^{k}\times(1 - p)^{n - k}$, where $n$ is the number of trials, $k$ is the number of successes, $p$ is the probability of success on a single trial, and $C(n,k)=\frac{n!}{k!(n - k)!}$. Here, $n = 10$, $p=0.14$, and $1 - p = 0.86$.

Step2: Answer part (a)

For $k = 0$, $C(10,0)=\frac{10!}{0!(10 - 0)!}=1$. Then $P(X = 0)=C(10,0)\times(0.14)^{0}\times(0.86)^{10}=1\times1\times0.2213 = 0.2213$.

Step3: Answer part (b)

For $k = 1$, $C(10,1)=\frac{10!}{1!(10 - 1)!}=\frac{10!}{1!9!}=10$. Then $P(X = 1)=C(10,1)\times(0.14)^{1}\times(0.86)^{9}=10\times0.14\times0.2574=0.3603$.

Step4: Answer part (c)

$P(X = 0\text{ or }X = 1)=P(X = 0)+P(X = 1)=0.2213 + 0.3603=0.5816$.

Step5: Answer part (d)

A result is significantly low if $P(X\leq k)\leq0.05$. Since $P(X = 0\text{ or }X = 1)=0.5816>0.05$, 1 is not a significantly low number.

Answer:

a. 0.2213
b. 0.3603
c. 0.5816
d. No, because the probability that 0 or 1 of the selected adults say that they were too young is greater than 0.05.