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3 years ago

If x is a number, which expression represents the statement below? 4 less than the product of 2 and a number

Mathematics

1 answer:

yulyashka [42]3 years ago

3 0

Answer:

2x-4

Step-by-step explanation:

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A commuter must pass through 5 traffic lights on her way to work and will have to stop at each one that is red. She estimates th

sergij07 [2.7K]

Answer:

(a) The mean or expected value of X is 2.2.

(b) The standard deviation of X is 1.3.

Step-by-step explanation:

Let X = number of times the traffic light is red when a commuter passes through the traffic lights.

The probability distribution of X id provided.

The formula to compute the mean or expected value of X is:

$\mu=E(X)=\sum x.P(X=x)$

The formula to compute the standard deviation of X is:

$\sigma=\sqrt{E(X^{2})-(E(X))^{2}}$

The formula of E (X²) is:

$E(X^{2})=\sum x^{2}.P(X=x)$

(a)

Compute the expected value of X as follows:

$E(X)=\sum x.P(X=x)\\=(0\times0.06)+(1\times0.25)+(2\times0.35)+(3\times0.15)+(4\times0.13)+(5\times0.06)\\=2.22\\\approx2.2$

Thus, the mean or expected value of X is 2.2.

(b)

Compute the value of E (X²) as follows:

$E(X^{2})=\sum x^{2}.P(X=x)\\=(0^{2}\times0.06)+(1^{2}\times0.25)+(2^{2}\times0.35)+(3^{2}\times0.15)+(4^{2}\times0.13)+(5^{2}\times0.06)\\=6.58$

Compute the standard deviation of X as follows:

$\sigma=\sqrt{E(X^{2})-(E(X))^{2}}\\=\sqrt{6.58-(2.22)^{2}}\\=\sqrt{1.6516}\\=1.285\\\approx1.3$

Thus, the standard deviation of X is 1.3.

4 0

3 years ago

Read 2 more answers

What is 19.2×10^8 minutes in hours

Nuetrik [128]

Hi!

$19.2*10^8$

$10^8=100,000,000$

$100,000,000*19.2$

$Answer-->=1,920,000,000$

Explanation: This question is super easy. First you had to used 10^8 and it gave us 100,000,000. You can also multiply by 19.2*100,000,000 and it gave us the answer is 1,920,000,000 is the right answer. Hope this helps! And thank you for posting your question at here on Brainly. And have a great day. -Charlie

6 0

3 years ago

In a school there are 600 teachers ad 1200 students

8_murik_8 [283]

Answer:

Can you please give a clearer explanation of what is your question?

Step-by-step explanation:

8 0

3 years ago

Question 2

cluponka [151]

Answer:

4:5

Step-by-step explanation:

28:35

28/7:35/7

4:5

hopefully this helps :)

4 0

2 years ago

Ill mark brainlist plss help

tresset_1 [31]

It’s 10. This is because 27/3 is 9 so the ratio is by 9

6 0

3 years ago