What is the y and x intercept ? y= x=

Consider a paint-drying situation in which drying time for a test specimen is normally distributed with σ = 7. The hypotheses H0

pshichka [43]

Answer:

(a) The value $\bar x$ = 72.3 is 1.21 standard deviations below the null value of μ.

(b) The mean drying time of paint is not less than 74.

Step-by-step explanation:

The hypothesis for the single mean test is:

H₀: μ = 74 vs. Hₐ: μ < 74.

The information provided is:

σ = 7

n = 25

As the population standard deviation is known, we will use a z-test for single mean.

(a)

The z-score is a Normal distribution with mean 0 and variance 1. It is also defined as the number of standard deviations a raw score is from the mean.

The z-score for sample mean is given by:

$z=\frac{\bar x-\mu}{\sigma/\sqrt{n}}$

If $\bar x$ = 72.3 compute the corresponding z-score as follows:

$z=\frac{\bar x-\mu}{\sigma/\sqrt{n}}$

$=\frac{72.3-74}{7/\sqrt{25}}\\=-1.21$

Thus, the value $\bar x$ = 72.3 is 1.21 standard deviations below the null value of μ.

(b)

So the test statistic is, z = -1.21.

Compute the p-value of the test as follows:

$p-value=P(Z$

*Use a z-table.

The decision rule says to, reject the null hypothesis if the p-value is less than the significance level α = 0.01 and vice-versa.

p-value = 0.1131 < α = 0.01

The null hypothesis was failed to be rejected.

Thus, the mean drying time of paint is not less than 74.

6 0

2 years ago

An object is launched from a launching pad 144 ft. above the ground at a velocity of 128ft/sec. what is the maximum height reach

ollegr [7]

Answer:

18) a. h(x) = -16x² + vx + h(0) ⇒ h(x) = -16x² + 128x + 144

b. The maximum height = 400 feet

c. Attached graph

19) The rocket will reach the maximum height after 4 seconds

20) The rocket hits the ground after 9 seconds

Step-by-step explanation:

* Lets study the rule of motion for an object with constant acceleration

# The distance S = ut ± 1/2 at², where u is the initial velocity, t is the time

and a is the acceleration of gravity

# The vertical distances h in x second is h(x) - h(0), where h(0)

is the initial height of the object above the ground

∵ h(x) = vx + 1/2 ax², where h is the vrtical distance, v is the initial

velocity, a is the acceleration of gravity (32 feet/second²) and x

is the time

18)a.

∵ The value of a = -32 ft/sec² ⇒ negative because the direction

of the motion

is upward

∴ h(x) - h(0) = vx - (1/2)(32)(x²) ⇒ (1/2)(32) = 16

∴ h(x) = vx - 16x² + h(0)

∴ h(x) = -16x² + vx + h(0) ⇒ proved

* Find the height of the object after x seconds from the ground

∵ h(0) = 144 and v = 128 ft/sec

∴ h(x) = -16x² + 128x + 144

b.

* At the maximum height h'(x) = 0

∵ h'(x) = -32x + 128

∴ -32x + 128 = 0 ⇒ subtract 128 from both sides

∴ -32x = -128 ⇒ ÷ -32

∴ x = 4 seconds

- The time for the maximum height = 4 seconds

- Substitute this value of x in the equation of h(x)

∴ The maximum height = -16(4)² + 128(4) + 144 = 400 feet

c. Attached graph

19)

- The object will reach the maximum height after 4 seconds

20)

- When the rocket hits the ground h(x) = 0

∵ h(x) = -16x² + 128x + 144

∴ 0 = -16x² + 128x + 144 ⇒ divide the two sides by -16

∴ x² - 8x - 9 = 0 ⇒ use the factorization to find the value of x

∵ x² - 8x - 9 = 0

∴ (x - 9)( x + 1) = 0

∴ x - 9 = 0 OR x + 1 = 0

∴ x = 9 OR x = -1

- We will rejected -1 because there is no -ve value for the time

* The time for the object to hit the ground is 9 seconds

8 0

3 years ago

Hannah has 67.32 centimeters of wire. She uses 2 pieces of the wire.

mojhsa [17]

Answer:

38.46 (Rounded: 38.5)

Step-by-step explanation:

67.32-2(14.43)=38.46

3 0

3 years ago

What is the equation of the parabola?

irina1246 [14]

Because the parabola opens down and the vertex is at (0, 5), we conclude that the correct option is:

y = -(1/8)*x² + 5.

<h3>Which is the equation of the parabola?</h3>

The relevant information is that we have the vertex at (0, 5), and that the parabola opens downwards.

Remember that the parabola only opens downwards if the leading coefficient is negative. Then we can discard the two middle options.

Now, because the parabola has the point (0, 5), we know that when we evaluate the parabola in x = 0, we should get y = 5.

Then the constant term must be 5.

So the correct option is the first one:

y = -(1/8)*x² + 5.

If you want to learn more about parabolas:

brainly.com/question/4061870

#SPJ1

3 0

1 year ago

The volume of a box is found by multiplying its length, width, and height. The three sides are 0.5 foot, 0.75 foot, and 0.4 foot

just olya [345]

(1/2)×(3/4)×(2/5)=5/40=1/8

as a decimal, this is .125
for scientific notation, you must move the decimal one place to the right, so the answer is

1.25×10^-1 ft^3

4 0

3 years ago

Read 2 more answers