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2 years ago

I need help with this????

Mathematics

1 answer:

Mars2501 [29]2 years ago

3 0

Answer:

Step-by-step explanation:

X is either larger than -1 or smaller than 3 which is demonstrated in the equation in option A

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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

The absolute value of a negative fraction is always greater than 1, true of false?!

Fantom [35]

Answer: False

Step-by-step explanation: False because zero is negative or positive. The absolute value of any number could also include the absolute value of 0, which would be 0. Thus, the absolute value of any rational number is not always greater than zero, it can be zero as well. However, it is true that the absolute value of any rational number can never be negative.

Rational Number definition: Rationals contain whole numbers, integers, decimals, fractions, basically most numbers or any numbers.

6 0

2 years ago

950.3 divided by 37 were doing partial product divison

charle [14.2K]

I think it’s 25.6 or not

6 0

2 years ago

The sum of two consecutive even integers is 106. What are the integers?

Kruka [31]

Answer:

The integers are 52 and 54

Step-by-step explanation:

x = first even integer

x + 2 = next integer that is even

x + x + 2 = 106

2x + 2 = 106

2x = 104

x = 52

x + 2 = 54

4 0

1 year ago

A square in the board below and a letter in the word ATTENTION is chosen at

kolezko [41]

Answer:

4 /15

Step-by-step explanation:

From the number cube :

Count of Numbers greater than 4 = 16

Sample space of number cube = 20

P(number greater than 4) = 16 / 20 = 4/5

Word : ATTENTION

Count of letters in attention = 9

Count of T's in attention = 3

P(choosing T) = 3 / 9 = 1/3

P(greater than 4, then T) = 4/5 * 1/3 = 4 /15

5 0

2 years ago