Solve for the variable in 7 ∕28 = 25∕ x A. 20 B. 100 C. 4 D. 5

According to a 2018 survey by Bankrate, 20% of adults in the United States save nothing for retirement (CNBC website). Suppose t

nalin [4]

Answer:

0.5981 = 59.81% probability that three or less of the selected adults have saved nothing for retirement

Step-by-step explanation:

For each adult, there are only two possible outcomes. Either they save nothing for retirement, or they save something. The probability of an adult saving nothing for retirement is independent of any other adult. This means that the binomial probability distribution is used to solve this question.

Binomial probability distribution

The binomial probability is the probability of exactly x successes on n repeated trials, and X can only have two outcomes.

$P(X = x) = C_{n,x}.p^{x}.(1-p)^{n-x}$

In which $C_{n,x}$ is the number of different combinations of x objects from a set of n elements, given by the following formula.

$C_{n,x} = \frac{n!}{x!(n-x)!}$

And p is the probability of X happening.

20% of adults in the United States save nothing for retirement (CNBC website).

This means that $p = 0.2$

Suppose that sixteen adults in the United States are selected randomly.

This means that $n = 16$

What is the probability that three or less of the selected adults have saved nothing for retirement?

This is:

$P(X \leq 3) = P(X = 0) + P(X = 1) + P(X = 2) + P(X = 3)$

In which

$P(X = x) = C_{n,x}.p^{x}.(1-p)^{n-x}$

$P(X = 0) = C_{16,0}.(0.2)^{0}.(0.8)^{16} = 0.0281$

$P(X = 1) = C_{16,1}.(0.2)^{1}.(0.8)^{15} = 0.1126$

$P(X = 2) = C_{16,2}.(0.2)^{2}.(0.8)^{14} = 0.2111$

$P(X = 3) = C_{16,3}.(0.2)^{3}.(0.8)^{13} = 0.2463$

$P(X \leq 3) = P(X = 0) + P(X = 1) + P(X = 2) + P(X = 3) = 0.0281 + 0.1126 + 0.2111 + 0.2463 = 0.5981$

0.5981 = 59.81% probability that three or less of the selected adults have saved nothing for retirement

4 0

3 years ago

Three friends Steve, Jake and Jodie shared a pizza. Steve ate 2/5 of the pizza and Jake ate 1/4

nlexa [21]

Note that they together ate all of the pizza.
Therefore the total fractions they ate should add up to 1.

By letting the fraction Jodie ate be x.

x + 2/5 + 1/4 = 1
x = 7/20

The answer is 7/20.

3 0

3 years ago

Read 2 more answers

Pleaseeeeee help me i appreciate it

4vir4ik [10]

Answer:

Choice A (older trees are generally taller than younger trees)

Step-by-step explanation:

As you increase the x value, the y value tends to increase as well. Choice B is incorrect because the points are clustered together in a linear fashion, showing correlation. Choice C is incorrect because the fact that they are clustered around a line of best fit shows high correlation. Choice D is incorrect because a negative correlation coefficient would mean the y decreases as x increases.

7 0

3 years ago

The safety inspector in a large city wants to estimate the proportion of buildings in the city that are in violation of fire cod

storchak [24]

Answer:

Check Explanation.

Step-by-step explanation:

The sample will be a representative of the entire build us in the city.

For a sample size 35, 3 have fire code violations, hence, the proportion of houses with fire code violations = (3/35) = 0.0857 = 8.57 %

The uncertainty in the estimate is given in the form of standard error.

Standard error = √[(p(1-p)/n]

n = sample size = 35, p = 0.0857, 1 - p = 0.9143

Standard error of the sample = √(0.0857×0.9143/35) = 0.1616

In terms of the population, (0.1616/35) = 0.00462

Proportion of buildings with fire code violations = (8.57 ± 0.462) %

8 0

3 years ago

Pls helppp very easy c:

Zielflug [23.3K]

Answer:

2 56 0 56 18 0 3 0 20 12 12 54 7 64 18 25 24 0 0 28 14 8 6 24 35 9 27 48 40 1 0 3 18 16 8 7 0 0 36 48 49 28 40 42 15 6 27 16 36 8 0 32 81 4 30 0 0 9 32 10 30 2 45 16 5 0 0 14 35 18 0 54 0 12 36 24 4 8 10 18 72 6 63 12 0 21 0 24 63 0 21 20 9 15 45 0 6 72 5 4

Step-by-step explanation:

This hurt my soul but enjoy

7 0

2 years ago