14. A boy completes a 100 m circular track race in 5 min. Another boy runs in the same

The defect length of a corrosion defect in a pressurized steel pipe is normally distributed with mean value 30 mm and standard d

skelet666 [1.2K]

Answer:

$z=-0.842$

And if we solve for a we got

$a=30 -0.842*7.8=23.432$

So the value of height that separates the bottom 20% of data from the top 80% is 23.432.

Step-by-step explanation:

Let X the random variable that represent the heights of a population, and for this case we know the distribution for X is given by:

$X \sim N(30,7.8)$

Where $\mu=30$ and $\sigma=7.8$

For this part we want to find a value a, such that we satisfy this condition:

$P(X>a)=0.80$ (a)

$P(X$ (b)

As we can see on the figure attached the z value that satisfy the condition with 0.20 of the area on the left and 0.80 of the area on the right it's z=-0.842

If we use condition (b) from previous we have this:

$P(X$

$P(z$

But we know which value of z satisfy the previous equation so then we can do this:

$z=-0.842$

And if we solve for a we got

$a=30 -0.842*7.8=23.432$

So the value of height that separates the bottom 20% of data from the top 80% is 23.432.

8 0

3 years ago

The graph of F(x) can be stretched vertically and flipped over the x axis to produce the graph of G(x) if F(x)=x^2 which of the

ladessa [460]

Answer:

g(x) = -5x²

(option B)

Step-by-step explanation:

we know that our original graph, f(x) = x² is a parabola.

So, we can consider what happens when we adjust the function/equation of a parabola.

when we "vertically stretch" a parabola, we are increasing the value of x.

think of it this way: the steepness of a slope is rise over run. If we rise ten, and run one, that's going be a lot more steep than if we rise 1, run 1.

Let's say our x = 5

if f(x)=x²

f(5) = 25

> y value / steepness is 25

f(x) = 3x²

f(5) = 75

> y value / steepness is 75

So, we are looking for an equation with an increase in x present.

When a parabola has been flipped over the x-axis, we know that the original equation now includes a negative

suppose that x = 1

if y = x² ; y = 1² = 1

if y = -(x²) ; y = -(1²) ; y = -1

So, when we set x to be negative, we make our y-values end up as negative also (which makes the graph look as if it has been flipped upside-down)

This means that we are looking for a function with a negative x value.

So, we are looking for a negative x-value that is multiplied by a number >1

The graph that fits our requirements is g(x) = -5x²

hope this helps!!

6 0

2 years ago

What is the equivlalent expression of 6m

xenn [34]

Answer:

6 * m

Step-by-step explanation:

6m is is multiplication so should be the equivalent expression

Written out as words clearly says

six times a number

times meaning multiplication

Meaning any other expression is equivalent as long as it is a form of multiplication

If I'm wrong please tell me if not

Hope this helped :]

3 0

3 years ago

The force of gravity on an object varies directly with its mass. The constant of variation due to gravity is 32.2 feet per secon

castortr0y [4]

Answer:

Step-by-step explanation:

According to newton second law, the force of gravity on an object varies directly with its mass and it is expressed mathematically as Fαm i.e

F = mg where;

F is the force of gravity

m is the mass of the body

g is the proportionality constant known as the acceleration due to gravity.

If the constant of variation due to gravity is 32.2ft/s², the equation that represents F, the force on an object due to gravity according to m, the object’s mass can be gotten by substituting g = 32.2 into the formula above according to the law as shown;

F = m*32.2

F =32.2m

Hence the required equation is F = 32.2m

5 0

3 years ago

Read 2 more answers

N

Nataly_w [17]

Answer: four units left and 1 unit up

Step-by-step explanation:

because negative is at the bottom

4 0

3 years ago