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3 years ago

I will give out BRAINLIEST for the correct answer!

Mathematics

1 answer:

earnstyle [38]3 years ago

8 0

Answer:

Step-by-step explanation:

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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

Fabian harvests 10 pounds of tomatoes from his garden. He needs 225 pounds to make a batch of soup. If he sets aside 2.8 pounds

nadya68 [22]

He can make 3 batches of soup.

Starting with 10 pounds of tomatoes and taking out the number of pounds he sets aside for spaghetti sauce, 2.8, we have:
10-2.8 = 7.2 pounds left.

0.2 is read as "two tenths," so 7.2 = 7 2/10

We divide this remaining number of pounds by 2 2/5 for each batch of soup:

7 2/10 ÷ 2 2/5

Convert each to an improper fraction:
72/10 ÷ 12/5

Multiply by the reciprocal:
72/10 × 5/12 = 360/120 = 3

5 0

2 years ago

Please help me i don’t know how to solve this

murzikaleks [220]

Answer:

welp good luck ha

Step-by-step explanation:

3 0

3 years ago

In Sunday's Super Bowl, Tampa Bay ended up winning over Kansas City. With the win, Tampa Bay's Quarterback Tom Brady now has 7 C

Pavlova-9 [17]

Answer: