Which of the following is a result of shifting a circle with equation (x + 3)2 + (y

Leakage from underground gasoline tanks at service stations can damage the environment. It is estimated that 25% of these tanks

Gnesinka [82]

Answer:

a) 3.75

b) 23.61% probability that fewer than 3 tanks will be found to be leaking

c) 0% the probability that at least 600 of these tanks are leaking

Step-by-step explanation:

For each tank there are only two possible outcomes. EIther they leak, or they do not. The probability of a tank leaking is independent of other tanks. So we use the binomial probability distribution 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.

The expected value of the binomial distribution is:

$E(X) = np$

The standard deviation of the binomial distribution is:

$\sqrt{V(X)} = \sqrt{np(1-p)}$

To solve question c), i am going to approximate the binomial distribution to the normal.

Normal probability distribution

Problems of normally distributed samples can be solved using the z-score formula.

In a set with mean $\mu$ and standard deviation $\sigma$ , the zscore of a measure X is given by:

$Z = \frac{X - \mu}{\sigma}$

The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the pvalue, we get the probability that the value of the measure is greater than X.

When we are approximating a binomial distribution to a normal one, we have that $\mu = E(X)$ , $\sigma = \sqrt{V(X)}$ .

It is estimated that 25% of these tanks leak.

This means that $p = 0.25$

15 tanks chosen at random

This means that $n = 15$

a.What is the expected number of leaking tanks in such samples of 15?

$E(X) = np = 15*0.25 = 3.75$

b.What is the probability that fewer than 3 tanks will be found to be leaking?

$P(X < 3) = P(X = 0) + P(X = 1) + P(X = 2)$

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

$P(X = 0) = C_{15,0}.(0.25)^{0}.(0.75)^{15} = 0.0134$

$P(X = 1) = C_{15,1}.(0.25)^{1}.(0.75)^{14} = 0.0668$

$P(X = 2) = C_{15,2}.(0.25)^{2}.(0.75)^{13} = 0.1559$

$P(X < 3) = P(X = 0) + P(X = 1) + P(X = 2) = 0.0134 + 0.0668 + 0.1559 = 0.2361$

23.61% probability that fewer than 3 tanks will be found to be leaking

c.Now you do a larger study, examining a random sample of 2000 tanks nationally. What is the probability that at least 600 of these tanks are leaking?

Now we have n = 2000. So

$\mu = E(X) = np = 2000*0.25 = 500$

$\sigma = \sqrt{V(X)} = \sqrt{np(1-p)} = \sqrt{2000*0.25*0.75} = 19.36$

This probability is 1 subtracted by the pvalue of Z when X = 600. So

$Z = \frac{X - \mu}{\sigma}$

$Z = \frac{600 - 500}{19.36}$

$Z = 5.16$

$Z = 5.16$ has a pvalue of 0.

0% the probability that at least 600 of these tanks are leaking

4 0

3 years ago

let m represent the number of children playing soccer. those children are separated into four equal groups. write an expression

Mkey [24]

Answer:

m/4

Step-by-step explanation:

m is how many children are playing.

They are separated into 4 groups. Making it m(how many people are playing), out of 4.

For example, if m=12, then it would be 12/4, so 3 children will be in each group.

Hope this helps, you can change this to you own desire.

4 0

3 years ago

Solve 4X squared minus X -5 equals zero

Anettt [7]

your answer should be 1/3 if I did my math right

7 0

3 years ago

The standard IQ test has a mean of 102 and a standard deviation of 13. We want to be 98% certain that that we are within 5 IQ po

aleksklad [387]

Answer:

37

Step-by-step explanation:

Margin of error = critical value × standard error

For 98% confidence, CV = 2.326 (from t table).

Standard error is σ / √n, where σ is the population standard deviation, and n is the sample size.

Plugging in:

5 = 2.326 × 13 / √n

n = 36.6

Rounding up, n = 37.

5 0

4 years ago

Please help please!!!!!!!!!! ILL DO BRAINLIST PLSSS

svlad2 [7]

Answerdancer is 5.6 / 7 from the denominator in a plate holder to you / 62 Daniel divide to play Toda by 76 u x 2 x 36 do your ankles going to be 30 60 you're going to end up with 36 in your answer is going to be 76.30 mm

Step-by-step explanation:

it literally soo ezy

7 0

3 years ago

Which of the following is a result of shifting a circle with equation (x + 3)2 + (y - 5)2 = 36 right 3 units?