15% of the adults in a community cannot swim. If 20 adults are selected at rando

Question

15% of the adults in a community cannot swim. If 20 adults are selected at random from the community, what is the probability that exactly two of them cannot swim? Use formulas If 20 adults are selected at random from the communit hem cannot swim? Use your calculator. (Record the calculator command used as well as the result.) ind the mean and standard deviation for the number of adults who cannot swim in groups of size 20 om this population. Label them with the correct variables and round to the correct number of cimal places.

Explanation / Answer

Answer to the question)

P = 0.15

N = 20

P(x=2)

.

Formula of binomial probability:

P(X=x) = nCx *p^x (1-p)^(n-x)

.

On plugging the values we get:

P(x=2) = 20C2 * 0.15^2 * 0.85^18

P(x=2) = 0.2293

.

The calculator steps are:

2nd > vars > distr > binomcdf

The values to be entered are:

N = trials = 20

X = 2

P = 0.15

We get: P(X<=2) = 0.4049

.

Mean = n*p

Mean = 20*0.15

Mean = 3

.

Standard deviation = sqrt(n*p*(1-p))

Standard deviation = sqrt(20 * 0.15 *0.85)

Standard deviation = 1.5969

Related Questions

Navigate

• Browse (All)
• Browse 1
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.