Can someone explain this please?

g A sample of 3 items is chosen at random from a box containing 20 items, out of which 4 are defective. Let X be the number of d

professor190 [17]

Answer:

The variance and standard deviation of X are 0.48 and 0.693 respectively.

The variance and standard deviation of (20 - X) are 0.48 and 0.693 respectively.

Step-by-step explanation:

The variable X is defined as, X = number of defective items in the sample.

In a sample of 20 items there are 4 defective items.

The probability of selecting a defective item is:

$P (X)=\frac{4}{20}=0.20$

A random sample of n = 3 items are selected at random.

The random variable X follows a Binomial distribution with parameters n = 3 and p = 0.20.

The variance of a Binomial distribution is:

$V(X)=np(1-p)$

Compute the variance of X as follows:

$V(X)=np(1-p)=3\times0.20\times(1-0.20)=0.48$

Compute the standard deviation (σ (X)) as follows:

$\sigma (X)=\sqrt{V(X)}=\sqrt{0.48}=0.693$

Thus, the variance and standard deviation of X are 0.48 and 0.693 respectively.

Now compute the variance of (20 - X) as follows:

$V(20-X)=V(20)+V(X)-2Cov(20,X)=0+0.48-0=0.48$

Compute the standard deviation of (20 - X) as follows:

$\sigma (20-X)=\sqrt{V(20-X)} =\sqrt{0.48}0.693$

Thus, the variance and standard deviation of (20 - X) are 0.48 and 0.693 respectively.

3 0

2 years ago

Helpppppp again unicorn

belka [17]

Answer:

1 . given

2. given

3. transitive properties of congruence ...

4 .AAS

5 0

2 years ago

Read 2 more answers

Find the area of the trapezoidal prism?

Olenka [21]

Answer: The formula is (b1 + b2)h+PH

Step-by-step explanation:

4 0

3 years ago

The upper-left coordinates on a rectangle are (-5, 6)(−5,6)left parenthesis, minus, 5, comma, 6, right parenthesis, and the uppe

sammy [17]

Answer:

Step-by-step explanation:

The question is incomplete. Here is the complete question.

The upper-left coordinates on a rectangle are (−5,6) and the upper-right coordinates are (−2,6). The rectangle has a perimeter of 16units. Draw the rectangle on the coordinate plane below.

If the coordinates of the top of the triangle (breadth) is (−5,6) and (−2,6), we can calculate the breadth of the rectangle by taking the difference between the two points using the formula:

D = √(y₂-y₁)²+(x₂-x₁)²

Given x₁ = -5, y₁= 6, x₂ = -2 and y₂ = 6

D = √(6-6)²+(-2-(-5))²

D = √0²+3²

D = √9

D = 3 units

Breadth = 3 units

Given the Perimeter to be 16 units and the formula for calculating the perimeter of rectangle t be P = 2(L+B), we can get the length of the rectangle.

16 = 2(3+L)

16 = 6+2L

16-6 = 2L

2L = 10

L = 10/2

L = 5 units.

Hence the length of the rectangle is 5 units and the breadth is 3 units. Find the diagram in the attachment.

7 0

3 years ago

Ian tosses a bone up in the air for his dog, Spot. The height, h, in feet, that Spot is above the ground at the time t seconds a

kirill115 [55]

Answer:

12 feet per second.

Step-by-step explanation:

Please consider the complete question.

Ian tosses a bone up in the air for his dog, Spot. The height, h, in feet, that Spot is above the ground at the time t seconds after she jumps for the bone can be represented $h(t)=-16t^2+20t$ .