6x – 2y = 10 2x + 3y = 51 Solving the first equation above for y gives: y = x – 5

Answer:

There is enough evidence to support the claim that the batteries power the laptops for significantly less than 4 hours. (P-value = 0).

The null and alternative hypothesis are:

[tex]H_0: \mu=4\\\\H_a:\mu< 4[/tex]

Step-by-step explanation:

The question is incomplete: To test this claim a sample or population standard deviation is needed.

We will estimate that the sample standard deviation is 2 hours, and use a t-test to test that claim.

NOTE (after solving): The difference between the sample mean and the mean of the null hypothesis is big enough to reject the null hypothesis, even when we have a sample standard deviation of 3.5 hours, which can be considered bigger than the maximum standard deviation for the sample.

This is a hypothesis test for the population mean.

The claim is that the batteries power the laptops for significantly less than 4 hours.

Then, the null and alternative hypothesis are:

[tex]H_0: \mu=4\\\\H_a:\mu< 4[/tex]

The significance level is 0.05.

The sample has a size n=500.

The sample mean is M=3.5.

As the standard deviation of the population is not known, we estimate it with the sample standard deviation, that has a value of s=2.

The estimated standard error of the mean is computed using the formula:

[tex]s_M=\dfrac{s}{\sqrt{n}}=\dfrac{2}{\sqrt{500}}=0.0894[/tex]

Then, we can calculate the t-statistic as:

[tex]t=\dfrac{M-\mu}{s/\sqrt{n}}=\dfrac{3.5-4}{0.0894}=\dfrac{-0.5}{0.0894}=-5.5902[/tex]

The degrees of freedom for this sample size are:

[tex]df=n-1=500-1=499[/tex]

This test is a left-tailed test, with 499 degrees of freedom and t=-5.5902, so the P-value for this test is calculated as (using a t-table):

[tex]P-value=P(t<-5.5902)=0[/tex]

As the P-value (0) is smaller than the significance level (0.05), the effect is  significant.

The null hypothesis is rejected.

There is enough evidence to support the claim that the batteries power the laptops for significantly less than 4 hours.

Answer:

Step-by-step explanation:

Hello!

Given the data for the variables:

Y: Selling price of a house on the shore of Tawas Bay

X₁: Number of bathrooms of a house on the shore of Tawas Bay.

X₂: Square feet of a house on the shore of Tawas Bay.

X₃: Number of bedrooms of a house on the shore of Tawas Bay.

The multiple regression model is Y= α + β₁X₁ + β₂X₂ + β₃X₃ + εi

a. Using software I've entered the raw data and estimated the regression coefficients:

^α= a= -5531.01

Represents the mean selling price of the houses when 0 bathrooms, 0 square feet and 0 bedrooms.

^β₁= b₁= -1386.21

Represents the modification of the mean selling price of the houses when the number of bathrooms increases in one unit and the square feet and number of bedrooms remain unchanged.

^β₂= b₂= 60.28

Represents the modification of the mean selling price of the houses when the square feet increase in one unit and the number of bathrooms and bedrooms remain unchanged.

^ β₃= b₃= 54797.08

Represents the modification of the mean selling price of the houses when the number of bedrooms increase in one unit and the number of bathrooms and square feet of the houses remain unchanged.

^Y= -5531.01 -1386.21X₁ + 60.28X₂ + 54797.08X₃

b)

R²= 0.55

R²Aj= 0.49

The coefficient of determination gives you an idea of how much of the variability of the dependent variable (Y) is due to the explanatory variables. Each time you add another explanatory variable to the regression the coefficient increases regarding of real contribution of the new variable. This could lead to thinking (wrongly) that the new variables are good to explain the dependent variable.  

The adjusted coefficient of determination is a correction made to the raw coefficient of determination to have a more unbiased estimation of the effect the independent variables have over the dependent variable.

⇒ As you can see both coefficient are around 50%, which means that these explanatory variables

c)

The standard error estimate, this is the estimate of the population variance of the errors. In the ANOVA is represented by the Mean Square of the errors (MME)

Se²= MME= 3837640577.01

Se= 61948.6931

d) and f)

For the hypotheses tests for each slope the t- and p-values are:

α: 0.05

β₁: [tex]t_{H_0}= \frac{b_1-\beta_1 }{Sb_1}[/tex] t= -0.06; p-value: 0.9528 ⇒ Do not reject H₀, the test is not significant.

β₂: [tex]t_{H_0}= \frac{b_2-\beta_2 }{Sb_2}[/tex] t= 2.56; p-value: 0.0180 ⇒ Reject H₀, the test is significant.

β₃: [tex]t_{H_0}= \frac{b_3-\beta_3 }{Sb_3}[/tex] t= 2.28; p-value: 0.0326 ⇒ Reject H₀, the test is significant.

e)

H₀: β₁= β₂= β₃

H₁: At least one βi is different from the others ∀ i=1, 2, 3

α: 0.05

F= 9.03

p-value: 0.0004

⇒ Reject H₀, the test is significant.

I hope it helps!

Answer:

A.

Step-by-step explanation:

Volume of sphere = (4/3)πr³

= 4/3(3.14)(d/2)³

= 4/3(3.14)(7/2)³

= 4/3(3.14)(3.5)³

= 4/3(3.14)(42.875)

= (1.33)(3.14)(42.875)

= 179.5 cm³

Answer:

The answer is 179.5 cm^2

Answer:

Predicted response value = 39.536

Note that this predicted response value will most likely be far from the actual response value because the correlation coefficient of the regression equation used (r = 0.39) is too far away from 1.

Step-by-step explanation:

The response variable is the dependent variable (y) whose value is obtained from the expression involving the independent variable (x).

For this question, although the correlation coefficient, r = 0.39, is far from 1, the regression equation is

y = 0.495x - 14.914

The predicted response value will be obtained from the explanatory variable and the regression equation

x = 110

y = 0.495x - 14.914

y = (0.495×110) - 14.914 = 39.536

Note that this predicted response value will most likely be far from the actual response value because the correlation coefficient of the regression equation used (r = 0.39) is too far away from 1.

Hope this Helps!!!

Answer:

See below

Step-by-step explanation:

a.

[tex]\dfrac{10}{4}=\dfrac{5(2)}{2(2)}=\dfrac{5}{2}[/tex]

b.

[tex]\dfrac{20}{15}=\dfrac{4(5)}{3(5)}=\dfrac{4}{3}[/tex]

c.

[tex]\dfrac{-24}{42}=\dfrac{-4(6)}{7(6)}=\dfrac{-4}{7}[/tex]

d.

[tex]\dfrac{-18}{-14}=\dfrac{-2(9)}{-2(7)}=\dfrac{9}{7}[/tex]

Hope this helps!

Answer:

Step-by-step explanation:

To solve this problem, we need to find the number which express the whole park.

Notice that the park is divided in two sections, one occupies 5/8 of the total, and the other occupies 2/7 of the total. So, the sum would be

[tex]\frac{5}{8}+\frac{2}{7}=\frac{35+16}{56} =\frac{51}{56}[/tex]

Now we have the total space there, we need to divide 5/8 by 51/56, so

[tex]\frac{5}{8} \div \frac{51}{56}=\frac{5}{8} \times \frac{56}{51}=\frac{280}{408} \approx 0.69[/tex]

Therefore, the rink occupies 69% of the whole park, approximately, which is equivalent to 280/408.

Answer:

[tex]A(t) = 2,000(1.05)^{t}[/tex]

Step-by-step explanation:

The compound interest formula is given by:

[tex]A(t) = P(1 + \frac{r}{n})^{nt}[/tex]

Where A(t) is the amount of money after t years, P is the principal(the initial sum of money), r is the interest rate(as a decimal value), n is the number of times that interest is compounded per year and t is the time in years for which the money is invested or borrowed.

You invest $2,000

This means that [tex]P = 2,000[/tex]

Compounded anually

Once a year, so [tex]n = 1[/tex]

Interest rate of 5%.

This means that [tex]r = 0.05[/tex]

Amount after t years:

[tex]A(t) = P(1 + \frac{r}{n})^{nt}[/tex]

[tex]A(t) = 2,000(1 + \frac{0.05}{1})^{t}[/tex]

[tex]A(t) = 2,000(1.05)^{t}[/tex]

Answer:

There are 210 ways

Step-by-step explanation:

The number of ways or combinations in which we can select x elements from a group of n elements where the order doesn't matter can be calculated as:

[tex]nCx=\frac{n!}{x!(n-x)!}[/tex]

So, we have 10 teaching assistants and we need to choose 4 (one assistant per question) to grade each question. It means that n is equal to 10 and x is equal to 4.

Therefore, the number of ways that the assistants can be chosen to grade the exam are calculated as:

[tex]10C4=\frac{10!}{4!(10-4)!}=210[/tex]

Answer:

  90

Step-by-step explanation:

The family filters 5 gallons per day, so can expect to use the filter for ...

  (450 gal)/(5 gal/day) = 90 day

After 90 days of average water use, the family will need to replace the filter.

Answer:

Please read the complete answer below!

Step-by-step explanation:

You have the following function:

[tex]f(x)=x^3-3x^2-9x+4[/tex]   (1)

a) To find the interval on which f is increasing or decreasing, you first calculate the critical points of f(x).

You calculate the derivative f(x) respect to x:

[tex]\frac{df}{dx}=3x^2-6x-9[/tex]    (2)

Next, you equal the derivative to zero, and then you find the roots of the polynomial by using the quadratic formula:

[tex]3x^2-6x-9=0\\\\x_{1,2}=\frac{-(-6)\pm\sqrt{(-6)^2-4(3)(-9)}}{2(3)}\\\\x_{1,2}=\frac{6\pm12}{6}\\\\x_1=-1\\\\x_2=3[/tex]

Then, the critical points are x=-1 and x=3

Next, you calculate df/dx for a values of x to the left and to the right of the critical points x1 and x2. If df/dx < 0 the function is decreasing, if df/dx > 0 the function is increasing.

for x = -1.01

[tex]\frac{df(-1.01)}{dx}=3(-1.01)^2-6(-1.01)-9=0.12[/tex]

Then, in the interval (-∞,-1), the function is increasing

for x = -0.99

[tex]\frac{df(-0.99)}{dx}=3(-0.99)^2-6(-0.99)-9=-0.11[/tex]

In the interval (-1,3) the function is decreasing

for x = 3.01

[tex]\frac{df(3.01)}{dx}=3(3.01)^2-6(3.01)-9=0.12[/tex]

In the interval (3,+∞) the function is increasing

b) To find the local minimum and maximum you use the second derivative of the function:

[tex]\frac{d^2f}{dx^2}=6x-6[/tex]     (3)

you evaluate the second derivative for the critical points x1 and x2, if the second derivative is positive, you have a local minimum. If the second derivative is negative, you have a local maximum:

for x1 = -1

[tex]6(-1)-6=-12<0[/tex]

x=-1 is a local maximum

for x2 = 3

[tex]6(3)-6=12>0[/tex]

x=3 is a local minimum

c) upward concavity: (-1,3)

downward concavity: (-∞,-1)U(3,+∞)

The inflection points are calculated with the second derivative equal to zero:

[tex]6x-6=0\\\\x=1[/tex]

For x = 1 you have an inflection point

Answer:

a) The function is [tex]f(x,y,z) = xyz+2z^2[/tex]

b) The value of the integral is 18

Step-by-step explanation:

a) We are given that [tex] F(x,y,z) (yz,xz,xy+4z)[/tex]. We want to find a function f such that the gradient of f is F. That is [tex]\nablda f = F[/tex] . Suppose that such f does exist, if that is the case, then by definition of the gradient, we have that

[tex] F(x,y,z) = (\frac{\partial f}{\partial x},\frac{\partial f}{\partial y},\frac{\partial f}{\partial z})[/tex]

From here, we have that

[tex] yz = \frac{\partial f}{\partial x}[/tex]

if we integrate both sides with respect to x, we get that

[tex] f(x,y,z) = xyz+ g(y,z)[/tex]

where g is a function that depens on y and z only. Now, we differentiate this equation with respect to y and make it equal to the 2nd component of F. That is

[tex] xz + \frac{\partial g}\partial{y} = xz[/tex]

This implies that [tex]\frac{\partial g}{\partial y} =0[/tex]. This means that g actually depends only on z. Until now, f is of the form

[tex] f(x,y,z) = xyz+g(z)[/tex]

If we repeat the previous step, by differentiating with respect to z and making it equall to the third component of F we get

[tex] xy + \frac{\partial g}{\partial z} = xy + 4z[/tex]

This implies that [tex] \frac{\partial g}{\partial z} = 4z[/tex] . If we integrate both sides with respect to z, we get that [tex] g(z) = 2z^2[/tex]

So f is of the form [tex] f(x,y,z) = xyz+2z^2[/tex]

b) To calculate the integral over the given segment, we can use the function f. Since the path is from (1,0,-2) to (6,4,1), then the value of the integral is given by evaluatin f at the end point and the substracting the value of f at the start point, that is

[tex] \int_C F \cdot dr = f(6,4,1) -f(1,0,-2) = 24+2(1)^2- (0+2(-2)^2)) = 18[/tex]

Answer:

5(4) + 5(8)

Step-by-step explanation:

Through destributive property, 5 is multiplied by both 4 and 8

Answer:

the person above is right thank and five star them

Step-by-step explanation:

So first, you want to isolate your Y. To do this, you must get it alone on ONE SIDE of the equation.

5x - 2y = 3

-5x         -5x

[tex]\frac{-2y}{-2}[/tex] = [tex]\frac{3-5x}{-2}[/tex]

ANSWER: y = \frac{3-5x}{-2}

Step-by-step explanation:

We need the function f(x) to be able to determine the required.

Suppose we were given a function

f(x) = y

f'(x) represents the first derivative of the function f(x) = y.

f'(1) represents the value of the first derivative of the function f(x) = y after replacing x by 1.

f'(5) represents the value of the first derivative of the function f(x) = y after replacing x by 5.

Example: Suppose f(x) = x² + 3x, find

f'(x), f'(1), and f'(5).

f'(x) = 2x + 3

f'(1) = 2(1) + 3 = 5

f'(5) = 2(5) + 3 = 13

Answer:

B:

Step-by-step explanation:

If we rotate the 3-D figure around y-axis we'll obtain a cone with a radius of 3 units

Answer:

C. [tex]G(x)=\frac{1}{x} -2[/tex]

Step-by-step explanation:

→For the function G(x) to shift downwards 2 units, there must be a 2 being subtracted.

----------------------------------------------------------------------------------------------------

F(x) + c

-Vertical shift and the function is moved c units

-Graph shifts c units up for F(x) + c and c units down for F(x) - c

----------------------------------------------------------------------------------------------------

This means the correct answer is "C. [tex]G(x)=\frac{1}{x} -2[/tex]."

Complete question:

Mai is making personal pizzas. For 4 pizzas, she uses 10 ounces of cheese.

a. How much cheese does Mai use per Pizza

b. At this rate how much cheese will she need to make 15 Pizza's

Answer:

a. ounces of cheese per pizza = 10/4 = 2.5 ounces of cheese

b. amount of cheese to make 15 pizzas= 2.5 × 15 = 37.5 ounces of cheese

Step-by-step explanation:

Mai is making a personal pizzas .For 4 pizza she uses 10 ounces of cheese. This means Mai uses 10 ounces of cheese in weight to make just 4 pizzas.

a. How much cheese does Mai use per Pizza

Not she uses 10 ounces of cheese to make 4 pizzas. Therefore,

If 4 pizzas requires  10 ounces of cheese

1 pizza will require ? ounces of cheese

cross multiply

ounces of cheese per pizza = 10/4 = 2.5 ounces of cheese

b. At this rate how much cheese will she need to make 15 Pizza's

Since she requires 2.5 ounces of cheese to make 1 pizza

? ounces of cheese will be required to make 15 pizzas

cross multiply

amount of cheese to make 15 pizzas = 2.5 × 15 = 37.5 ounces of cheese

Answer:

  C  Both (-2,13) and (-1,7)

Step-by-step explanation:

Try the offered points in the equation and see if they work

  y = -6x +1

For (-2, 13):

  13 = -6(-2) +1 = 12 +1 . . . . true

For (-1. 7):

  7 = -6(-1) +1 = 6 +1 . . . . true

Both ordered pairs are solutions.

Answer:

140

Step-by-step explanation:

Because the lines are parallel:

[tex]\dfrac{DE}{35}=\dfrac{60}{15} \\\\DE=4\cdot 35=140[/tex]

Hope this helps!

Answer:

32

Step-by-step explanation:

Answer:

C............PAC-MAN

Step-by-step explanation:

Answer:

12/13 ; 5/13; 12/5

Step-by-step explanation:

sinx =5/13 =opposite/ hypothenus

By Pythagoras rule the hypothenus side can be obtained as

√ 13^2 -5^2 = √169 -25 = √144 = 12

cos x= adjacent/ hypothenus = 12/13

Now Cos2x= Sinx

And Sin2x = Cosx

Hence ;

Sin2x=12/13

Cos2x =5/13

Tan2x= Sin 2x/ Cos 2x

= 12/13 ÷ 5/13

= 12/13 × 13/5 = 12/5

Answer:

2.5

Step-by-step explanation:

We have that the standardized mortality ratio (SMR) is the relationship between the number of deaths observed in a year, that is, those that occurred and the number of expected deaths, that is, those that were predicted.

SMR = observed / expected

therefore if we replace we have:

SMR = 4500/1800

SMR = 2.5

Which means that the standardized mortality ratio (SMR) is 2.5

Answer:

2

Step-by-step explanation:

g(x) = 1/2x - 1

g(6= 1/2*6-1= 3-1= 2

Answer:

Step-by-step explanation:

The objective here is to create a journal entry for the Star corporation treasure stock transaction, then find the total amount of Paid-in Capital from Treasury Stock at December 31, 2017.

Journal Entries:

Date                  Description                          $                      $

Mar 1                Treasury Stock                   40,000  

Cash                                                                                   40,000

June 1               Cash(1,000*12)                     12,000  

                       Treasury Stock(1,000*8)                               8,000

                        Paid in Capital(12-8)*1,000                           4,000

Sept 1                Cash(1,000*10)                       10,000  

                      Treasury Stock (1,000*8)                               8,000

                      Paid in Capital (12-10)*1,000                          2,000

Dec 1               Cash (1,000*7)                             7,000  

                     Paid in Capital (8-7)*1,000             1,000  

                     Treasury Stock (1,000*8)                                 8,000

The Beginning Balance:

Treasury Stock Price = 250,000 / 5,000

= $50

Paid in Capital = [2,000×(53-50) + 2,000×(48-50) + 1,000×(43-50)]

= [(2,000×3) + (2,000×-2) + (1,000×-7)]

= 6,000 - 4,000 - 7,000

= -5,000

During the year transactions = 4,000+2,000-1,000

= $5,000

The total amount paid in Capital = Beginning Balance + During the year transactions  

= -5,000 + 5,000

= 0

Some other circumstances under which company can go for the purchase of treasury stock includes:

A situation where by they resells  the stock in the bid to increase funds for future investment.

The company can go for the purchase of treasury stock in order to empower the financial ratios and have full control interest in the company

It can also aid as a means of increasing the price of the share when it is underpriced in the market.

Answer:

18

Step-by-step explanation:

Let x represent the years ago

103-x = 5(35-x)

103-x = 175 +5x

4x = 72

x = 18

Answer:

i

Step-by-step explanation:

Why is i the square root of negative one?

The term "imaginary" is used because there is no real number having a negative square. There are two complex square roots of −1, namely i and −i, just as there are two complex square roots of every real number other than zero, which has one double square root.

Answer:

A. or every 1 ton increase in precompression stress, the shear strength of the joint is estimated to increase by 0.987 tons.

Step-by-step explanation:

Hello!

The engineers created a regression model to estimate the relationship between the "shear strength of masonry joints" (Y), measured in tons, and the "precompression stress" (X), measured in tons.

^Y= a + bXi

Using the regression output:

Estimate of the y-intercept: a= 1.192

Estimate of the slope: b= 0.987

In general terms you can interpret the slope as:

"Is the modification of the estimated mean of Y when X increases one unit"

In this case it means that every time the precompression stress increases one ton, the shear strength of the joint is estimated to increase 0.987 tons.

I hope this helps!

Answer:

Cases : 2623 school children , Explanatory Variable : Greenery or Vegetation around school , Response Variable : Children's Memory & attention spans , Yes  causation, Observational study

Step-by-step explanation:

a) Cases refers to the people or units of population studied in the research. In this case, it is sample of 2623 school children in Barcelona

b) Explanatory variable is variable which leads to, or causes the change in other variable. In this case, it is greenery or vegetation around researched students' schools

c) Response variable is the variable which is affected due to change in independent explanatory variable. In this case, it is children's working  memory & attention spans

d) Yes, the headline implies causation. As it implies cause effect relationship of greenery around children's school on their working memory & attention spans.

e) It is an observational study, as it observes the variables relationship as it is, without any specific experimental intervention.

Answer:

.66

Step-by-step explanation:

1minus .34

Correct me if I am wrong