Please help with these

If your good at math please help me with this question

solmaris [256]

Answer:

answer: 361.88

Hope that helps!

5 0

3 years ago

What is the formula for the expected number of successes in a binomial experiment with n trials and probability of success p? C

charle [14.2K]

Answer:

$(D)E[ X ] =np.$

Step-by-step explanation:

Given a binomial experiment with n trials and probability of success p,

$f(x)=\left(\begin{array}{c}n\\k\end{array}\right)p^x(1-p)^{n-x}, 0\leq x\leq n$

$E(X)=\sum_{x=0}^{n}xf(x)= \sum_{x=0}^{n}x\left(\begin{array}{c}n\\k\end{array}\right)p^x(1-p)^{n-x}$

Since each term of the summation is multiplied by x, the value of the term corresponding to x = 0 will be 0. Therefore the expected value becomes:

$E(X)=\sum_{x=1}^{n}x\left(\begin{array}{c}n\\x\end{array}\right)p^x(1-p)^{n-x}$

Now,

$x\left(\begin{array}{c}n\\x\end{array}\right)= \frac{xn!}{x!(n-x)!}=\frac{n!}{(x-)!(n-x)!}=\frac{n(n-1)!}{(x-1)!((n-1)-(x-1))!}=n\left(\begin{array}{c}n-1\\x-1\end{array}\right)$

Substituting,

$E(X)=\sum_{x=1}^{n}n\left(\begin{array}{c}n-1\\x-1\end{array}\right)p^x(1-p)^{n-x}$

Factoring out the n and one p from the above expression:

$E(X)=np\sum_{x=1}^{n}n\left(\begin{array}{c}n-1\\x-1\end{array}\right)p^{x-1}(1-p)^{(n-1)-(x-1)}$

Representing k=x-1 in the above gives us:

$E(X)=np\sum_{k=0}^{n}n\left(\begin{array}{c}n-1\\k\end{array}\right)p^{k}(1-p)^{(n-1)-k}$

This can then be written by the Binomial Formula as:

$E[ X ] = (np) (p +(1 - p))^{n -1 }= np.$

5 0

3 years ago

Predict what the graph of the following quadratic function will look like. (If you have a graphing calculator, you can use it to

Alex17521 [72]

Answer:

u-shaped; y-intercept (0,6); symmetrical with respect to the y-axis

Step-by-step explanation:

Given that y = 2x² + 6

The graph would be the shape of that of a parabola. It can be u shaped or n shaped depending on the value of the coefficient of a comparing with the standard equation y = ax² + bx + c. If a > 0, it is u shape and if a < 0, it is n shape.

For this question, since a > 0 it would be u shaped and the intercept can be gotten by putting x = 0.

Therefore y = 0² + 6 = 0

The intercept is at (0,6) and is symmetrical with respect to the y-axis

3 0

3 years ago

Can someone help with this pls it’s due today

KiRa [710]

D, hope this is right! :)

7 0

3 years ago

The cleaning service requires $39 in variable costs for cleaning materials. The fixed costs of labor, the company's truck, and a

user100 [1]

The average cost per cleaning service call charge by the company is $184.5.

<h3>What is an equation?</h3>

An equation is an expression that shows the relationship between two or more numbers and variables.

Let y represent the total cost for x number of service calls in a year. Hence:

y = 39x + 349200

For 200 service call, in a year, x = 200 * 12 = 2400

y = 39(2400) + 349200 = $442800

Average cost = $442800 / 2400 = 184.5

The average cost per cleaning service call charge by the company is $184.5.

Find out more on equation at: brainly.com/question/2972832

#SPJ1

8 0

2 years ago