According to a 2018 survey by Bankrate, 20% of adults in the United States save nothing for retirement (CNBC website). Suppose that twenty-one adults in the United States are selected randomly. What is the probability that more than five of the selected adults save nothing for retirement

0.769296

Step-by-step explanation:

The desired probability can be calculated from binomial probability distribution because there are 21 independent trials and probability of success(saving nothing for retirement) 0.2 remains same for each trial. Here, n=21 and p=0.20. We want to compute P(X>5).

The pdf of binomial distribution is

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

P(X>5)=1-P(X≤5)

P(X≤5)=P(X=0)+P(X=1)+P(X=2)+P(X=3)+P(X=4)+P(X=5)

P(X=0)=21C0*(0.2)^0*(1-0.2)^(21-0)=0.009223

P(X=1)=21C1*(0.2)^1*(1-0.2)^(21-1)=0.048423

P(X=2)=21C2*(0.2)^2*(1-0.2)^(21-2)=0.121057

P(X=3)=21C3*(0.2)^3*(1-0.2)^(21-3)=0.191673

P(X=4)=21C4*(0.2)^4*(1-0.2)^(21-4)=0.215632

P(X=5)=21C5*(0.2)^5*(1-0.2)^(21-5)=0.183287

P(X≤5)=0.009223+0.048423+0.121057+0.191673+0.215632+0.183287

P(X≤5)=0.769296

P(X≤5) can also be computed by using excel function BINOM.DIST(5,21,0.2,TRUE) which results in

P(X≤5)=0.769296.

7

step-by-step explanation:

i'm assuming you need to figure out how many campers go into each tent.

i got the answer by:

24+4=28

28/4=7  

b: |12 – x| ≤ 0.25

step-by-step explanation:      

let x be the possible lengths in inches, of the ribbons jaime cut.

we have been given that jaime is cutting strips of ribbon for a project. he tries to cut each piece to be 12 inches long, but sometimes he cuts it too long or too short by as much as 0.25 inch.  

we can represent this information in an inequality as:

by the definition of absolute value function we will get,

upon combining our inequalities we will get,

therefore, the inequality   describes all the possible lengths (x), in inches, of the ribbons jaime cut.

step-by-step explanation: