If the errors produced by a forecasting method for 3 observations are +3, +3, and −3, then what is the mean squared error?

Answer:

x = 5

Step-by-step explanation:

We know that AB = 2x - 3 and AB = 7, therefore:

2x - 3 = 7

2x - 3 + 3 = 7 + 3

2x = 10

2x / 2 = 10 / 2

x = 5

Answer:

Hey there!

We have tangent x=8/10

This simplifies to tangent x=0.8

Arctan=0.8, x=38.7 degrees.

Let me know if this helps :)

Answer:

38.7

Step-by-step explanation:

You are given the lengths of the legs of the triangle.

The trig ratio that relates the lengths of the legs is the tangent.

tan x = opp/adj

tan x = 8/10

tan x = 0.8

Use the inverse tangent function to find x.

tan^(-1) 0.8 = 38.7 deg

Answer: x = 38.7 deg

Answer:

$25

Step-by-step explanation:

.5 * 50 = 25

25<27.5<30

The cheapest supplier is the first one.

Answer:

[tex]\huge\boxed{6 ( 3d + 2 )}[/tex]

Step-by-step explanation:

18d + 12

The greatest common factor is 6, So we need to factor out 6

=> 6 ( 3d + 2 ) [Distributive property has been applied and this is the simplest form]

Answer:

6(3d+2)

Step-by-step explanation:

6 is the gcd of the two terms.

Answer:

-5

Step-by-step explanation:

Answer:

the answer is A

Step-by-step explanation: i have calculated this problom

Answer:

Step-by-step explanation:

14 + 5y

To solve the expression substitute the value of y that's - 1 into the expression

That's

14 + 5(-1)

= 14 - 5

= 9

Hope this helps you

Answer:

x = -6

y = 4

Step-by-step explanation:

Rewriting the equations :

Now, solving the two equations using substitution method, we get :

x = -6

y = 4

Answer:

y = 4

x = -6

Step-by-step explanation:

1/2 x + 1/4 y= -2        first equation

-2/3 x + 1/2 y = 6      second equation

solution:

from the first equation:

8(1/2 x + 1/4 y) = -2*8

8x*1/2 + 8y*1/4 = -16

8x/2 + 8y/4 = -16

4x + 2y = -16        third equation

from the second equation

6(-2/3 x + 1/2 y) = 6*6

6x*-2/3 + 6y*1/2 = 36

-12x/3 + 6y/2 = 36

-4x + 3y = 36        fourth equation

from the third & fourth equation:

 4x + 2y  = -16

-4x + 3y  = 36

   0  + 5y = 20

5y = 20

y = 20/5

y = 4

from the fourth equation:

-4x + 3y = 36

-4x + 3*4 = 36

-4x + 12 = 36

-4x = 36 - 12

-4x = 24

x = 24/-4

x = -6

Check:

from the first equation:

1/2 x + 1/4 y = -2

1/2 *-6 + 1/4 * 4 = -2

-3 + 1 0 -2

from the second equation:

-2/3 x + 1/2 y = 6

-2/3 * -6  +  1/2 * 4 = 6

4 + 2 = 6

Answer:

77:44

Step-by-step explanation:

Since 7:4 is equal to 11 and 121/11, each ratio can be multiplied by 11.

Answer and Step-by-step explanation:

Suppose that we have a number y which is a positive integer and that:

y = [tex]x_n...x_5x_4x_3x_2x_1x_0[/tex]

Where;

[tex]x_{0}[/tex] = digit at 10⁰ => one's place (units place)

[tex]x_1[/tex] = digit at 10¹ => 10's place (tens place)

[tex]x_{2}[/tex] = digit at 10² => 100's place (hundreds place)

[tex]x_{3}[/tex] = digit at 10³ => 1000's place (thousands place)

.

.

.

[tex]x_{n}[/tex] = digit at 10ⁿ place

Then;

y = [tex]x_{0}[/tex] * 10⁰ + [tex]x_1[/tex] * 10¹ + [tex]x_{2}[/tex] * 10² + [tex]x_{3}[/tex] * 10³ + [tex]x_{4}[/tex] * 10⁴ + [tex]x_5[/tex] * 10⁵ + . . . + [tex]x_{n}[/tex] * 10ⁿ

Since 10⁰ = 1, let's rewrite y as follows;

y = [tex]x_{0}[/tex]  + [tex]x_1[/tex] * 10¹ + [tex]x_{2}[/tex] * 10² + [tex]x_{3}[/tex] * 10³ + [tex]x_{4}[/tex] * 10⁴ + [tex]x_5[/tex] * 10⁵ + . . . + [tex]x_{n}[/tex] * 10ⁿ

Now, to test if y is divisible by 11, replace 10 in the equation above by -1. Since 10 divided by 11 gives -1 (mod 11)     [mod means modulus]

y = [tex]x_{0}[/tex]  + [tex]x_1[/tex] * (-1)¹ + [tex]x_{2}[/tex] * (-1)² + [tex]x_{3}[/tex] * (-1)³ + [tex]x_{4}[/tex] * (-1)⁴ + [tex]x_5[/tex] * (-1)⁵ + . . . + [tex]x_{n}[/tex] * (-1)ⁿ

=> y =  [tex]x_{0}[/tex]  - [tex]x_1[/tex] + [tex]x_{2}[/tex] - [tex]x_{3}[/tex] + [tex]x_{4}[/tex] - [tex]x_5[/tex] + . . . + [tex]x_{n}[/tex] (-1)ⁿ (mod 11)

Therefore, it can be seen that, y is divisible by 11 if and only if alternating sum of its digits [tex]x_{0}[/tex]  - [tex]x_1[/tex] + [tex]x_{2}[/tex] - [tex]x_{3}[/tex] + [tex]x_{4}[/tex] - [tex]x_5[/tex] + . . . + [tex]x_{n}[/tex] (-1)ⁿ is divisible by 11

Let's take an example

Check if the following is divisible by 11.

i. 1859

Solution

1859 is divisible by 11 if and only if the alternating sum of its digit is divisible by 11. i.e if (1 - 8 + 5 - 9) is divisible by 11.

1 - 8 + 5 - 9 = -11.

Since -11 is divisible by 11 so is 1859

ii. 31415

Solution

31415 is divisible by 11 if and only if the alternating sum of its digit is divisible by 11. i.e if (3 - 1 + 4 - 1 + 5) is divisible by 11.

3 - 1 + 4 - 1 + 5 = 10.

Since 10 is not divisible by 11 so is 31415 not divisible.

Answer:

Attachment 1 : Graph B

Attachment 2 : Option B

Step-by-step explanation:

( 1 ) The equation x = t² - 3 is represented by exponential growth, ( t² ) so it's graph will be similar to the first graph, graph 1, in our options. Then again we have to consider the equation y = √t - 2, which will be similar to graph 4, but with a greater slope. This leaves us with a solution of graph b.

( 2 ) We have the following system of equations at hand here.

{ x = 5 cot(t), y = - 3csc(t) + 4 }

Now instead of isolating the t from either equation, let's isolate cot(t) and csc(t) --- Step #1,

x = 5 cot(t) ⇒ x - 5 = cot(t),

y = - 3csc(t) + 4 ⇒ y - 4 = - 3csc(t) ⇒ y - 4 / - 3 = csc(t)

Now let's square these two equations, adding them --- Step #2

We know that csc²θ - cot²θ = 1, so let's subtract the equations

( y - 4 / - 3 )² = (csc(t))²

- ( x - 5 / 1 )² = (cot(t))²

___________________

(y - 4)² / 9 - x² / 25 = 1

And as we are subtracting the two expressions, this is an example of a hyperbola. Therefore your solution is option b.

Answer:

0

Step-by-step explanation:

Hello, please consider the following.

For any a and b real numbers we can write.

[tex](a-b)(a+b)=a^2-b^2[/tex]

We apply this formula two times here, as below.

[tex](x+1)(x^{2}+1)(x-1)=(x+1)(x-1)(x^{2}+1)\\\\=(x^2-1^2)(x^2+1)=(x^2-1)(x^2+1)\\\\=(x^2)^2-1^2=x^4-1[/tex]

We have the coefficient of 1 for [tex]x^4[/tex] and the constant term is -1, so the sum of the coefficients is 0.

Thank you.

Answer:

1

Step-by-step explanation:

(x + 1)(x² + 1)(x - 1)

= (x³ + x + x² + 1)(x - 1)

= x^4 - x³ + x² - x - x³ - x² + x - 1

= x^4 - 1

Coefficient of x^4 = 1

Answer:

Step-by-step explanation:

First you have to find the medians which is when you put the numbers in number order and find the one in the middle.

Class A: 60,65,70,70,75,80,80,85,90,90

=77.5

Class B: 75,85,85,85,90,90,90,90,95,100

=90

That the class B is more advanced, and they probably studied.

Answer:

Answer is below

Step-by-step explanation:

The width of the CI is directly proportional to critical value. When t* is greater than z value, the t value would then cause the margin of error to be larger and this will in turn cause the width of the confidence interval to be larger.

Greater t*df than z* gives us a bigger margin of error. This would in turn give bigger width of confidence interval. t distribution has greater width confidence interval compared to z distribution.

The width of confidence interval is a function of the margin of error. If the critical value of t(t*) is slightly larger than the critical value of z(z*), then the width of the confidence interval will be larger.

The margin of error is the product of the critical value and the standard error. Therefore, given the same standard error value, the value of the margin of error will increases based on the value of the critical value.

Since, t* is slightly larger than z*, then the confidence interval, t will be wider.

Learn more : https://brainly.com/question/18405415

Step-by-step explanation:

Hello, there!!!!

It's simple lets get started with simple solution.....

Given,

AC= 7cm

BC= 25cm

let AB be x.

Now, As it is a Right angled triangle, taking angle B as a refrence angle. we get,

h= BC= 25cm

p= AC= 7cm

b= AB= x

now, by Pythagoras relation we get,

[tex]b = \sqrt{ {h}^{2} - {p}^{2} } [/tex]

[tex]or \: b = \sqrt{ {25}^{2} - {7}^{2} } [/tex]

By simplifying it we get,

b= 24cm

Therefore, the value of AB is 24 cm.

Hope it helps...

Complete Question

Statistics professors believe the average number of headaches per semester for all students is more than 18. From a random sample of 15 students, the professors find the mean number of headaches is 19 and the standard deviation is 1.7. Assume the population distribution of number of headaches is normal.the correct conclusion at [tex]\alpha =0.001[/tex] is?

Answer:

There is no sufficient evidence to support the professor believe

Step-by-step explanation:

From the question we are told that

     The population mean is  [tex]\mu = 18[/tex]

     The sample size is  [tex]n = 15[/tex]

      The sample mean is  [tex]\= x = 19[/tex]

      The standard deviation is  [tex]\sigma = 1.7[/tex]

      The level of significance is  [tex]\alpha = 0.001[/tex]

The null hypothesis is  [tex]H_o: \mu = 18[/tex]

The  alternative hypothesis is  [tex]H_a : \mu > 18[/tex]

 The critical value of the level of significance from the normal distribution table is    

         [tex]Z_{\alpha } = 3.290527[/tex]

The test hypothesis is mathematically represented as

           [tex]t = \frac{\= x - \mu }{ \frac{\sigma}{ \sqrt{n} } }[/tex]

substituting values  

         [tex]t = \frac{ 19 - 18}{ \frac{1.7}{ \sqrt{15} } }[/tex]

         [tex]t = 2.28[/tex]

Looking at the value of  t and  [tex]Z_{\alpha }[/tex] we can see that [tex]t < Z_{\alpha }[/tex] so we fail to reject the null hypothesis.

This mean that there is no sufficient evidence to support the professor believe

Answer:  4 seconds

Step-by-step explanation:

x refers to time. Since we want to know how long it is in the air, we need to find the time (x) when the ball lands on the ground (y = 0)

0 = -12x² + 48x

0 = -12x(x - 4)

0 = -12x     0 = x - 4

0 = x          4 = x

x = 0 seconds is when the ball was kicked

x = 4 seconds is when the ball landed on the ground

Answer: The value of x- 2y is a. [tex]\pm 3[/tex].

Step-by-step explanation:

Given:  x and y are two positive real numbers such that [tex]x^2+4y^2=17[/tex]   and [tex]xy= 2[/tex] .

Consider [tex](x-2y)^2=x^2-2(x)(2y)+(2y)^2\ \ \ [(a+b)^2=(a^2-2ab+b^2)][/tex]

[tex]=x^2-4xy+4y^2[/tex]

[tex]=x^2+4y^2-4(xy)[/tex]

Put  [tex]x^2+4y^2=17[/tex]   and [tex]xy= 2[/tex] , we get

[tex](x-2y)^2=17-4(2)=17-8=9[/tex]

[tex]\Rightarrow\ (x-2y)^2=9[/tex]

Taking square root on both sides , we get'

[tex]x-2y= \pm3[/tex]

Hence, the value of x- 2y is a. [tex]\pm 3[/tex].

Answer:

The calculated value of z= 2.7225 falls in the critical region therefore we reject the null hypothesis and conclude that at the  5% significance level, true proportion of correct responses to the question without context exceeds that for the one with context.

Step-by-step explanation:

a: 15 % of 1000= 150

b. 15.96 % of $ 1000= $ 159.6

The customer would pay = $ 1000- $ 159.6= $ 840.4 and save $ 159.6

Formulate the hypotheses as

H0: p1= p2   true proportion of correct responses to the question without context is equal that for the one with context.

Ha : p1≠ p2

We choose the significance level ∝= 0.05

The critical value for two tailed test at alpha=0.05 is ± 1.96

The test statistic is

Z = p1-p2/ √pq (1/n1+ 1/n2)

p1= true proportion students who answered the question without context correctly  = 165/200=0.825

p2=  true proportion of students who answered the question with context correctly = 142/200= 0.71

p = an estimate of the common rate on the assumption that the two proportions are same.

p = n1p1+ n2p2/ n1 + n2

p =200 (0.825) + 200 (0.71) / 400

p=  165+ 142/400= 307 /400 =0.7675

now q = 1-p= 1- 0.7675= 0.2325

Thus

z= 0.825- 0.71/ √0.7675*0.2325( 1/200 + 1/200)

z= 0.115/√ 0.17844( 2/200)

z= 0.115/0.04224

z= 2.7225

The calculated value of z falls in the critical region therefore we reject the null hypothesis and conclude that at the  5% significance level, true proportion of correct responses to the question without context exceeds that for the one with context.

Answer:

Step-by-step explanation:

Given that:

mean μ = 70

sample size = 25

sample mean = 73

standard deviation = 7

level of significance = 0.10

The null hypothesis and the alternative hypothesis can be computed as follows:

[tex]\mathtt{H_o : \mu = 70} \\ \\ \mathtt{H_1 : \mu > 70 }[/tex]

The z score for this statistics can be calculated by using the formula:

[tex]z = \dfrac{X- \mu}{\dfrac{\sigma}{\sqrt{n}}}[/tex]

[tex]z = \dfrac{73- 70}{\dfrac{7}{\sqrt{25}}}[/tex]

[tex]z = \dfrac{3}{\dfrac{7}{5}}[/tex]

[tex]z = \dfrac{3 \times 5}{{7}{}}[/tex]

z = 2.143

At level of significance of 0.10

degree of freedom = n -1

degree of freedom = 25 - 1

degree of freedom = 24

The p - value from the z score at   level of significance of 0.10 and degree of freedom of 24 is:

P - value = 1 - (Z < 2.143)

P - value =  1 - 0.9839

P - value =  0.0161

Decision Rule: since P value is lesser than the level of significance, we reject the null hypothesis.

Conclusion: We conclude that energy drink consumption increases heart rate.

Answer:

H0: μd=0 Ha: μd≠0

t= 0.07607

On the basis of this we conclude that the mean weight differs between the two balances.

Step-by-step explanation:

The null and alternative hypotheses as

H0: μd=0 Ha: μd≠0

Significance level is set at ∝= 0.05

The critical region is t ( base alpha by 2 with df=5) ≥ ± 2.571

The test statistic under H0 is

t = d/ sd/ √n

Which has t distribution with n-1 degrees of freedom

Specimen        A               B           d = a - b         d²

1                     13.76        13.74         0.02           0.004

2                    12.47        12.45          0.02         0.004

3                    10.09        10.08           0.01        0.001

4                       8.91       8.92          -0.01          0.001

5                     13.57      13.54           0.03        0.009

6                     12.74      12.75          -0.01        0.001

∑                                                      0.06         0.0173

d`= ∑d/n= 0.006/6= 0.001

sd²= 1/6( 0.0173- 0.006²/6) = 1/6 ( 0.017294) = 0.002882

sd= 0.05368

t= 0.001/ 0.05368/ √6

t= 0.18629/2.449

t= 0.07607

Since the calculated value of t= 0.07607 does not falls in the rejection region we therefore accept the null hypothesis at 5 % significance level . On the basis of this we conclude that the mean weight differs between the two balances.

Answer:

see below

Step-by-step explanation:

4x + 10 = 2(2x + 5)

Distribute

4x+10 = 4x+10

Since the left side is identical to the right side, there are infinite solutions

4x - 5 = 4x + 10

Subtract 4x from each side

-5 = 10

This is never true, so there are no solutions

4x-5 = -5

Add 5 to each side

4x = 0

x=0

There is one solutions

Answer:

q > 27/61

Step-by-step explanation:

50q + 43 > −11q + 70

Add 11 q to each side

50q+11q + 43 > −11q+11q + 70

61q+43> 70

Subtract 43 from each side

61q> 27

Divide each side by 61

61q/61> 27/61

q > 27/61

Answer:

73%

Step-by-step explanation:

Answer:

[tex]\huge \boxed{\mathrm{\$ \ 7,533.33}}[/tex]

Step-by-step explanation:

There are 12 months in one whole year.

In one year, the person earns $96,600 with bonus.

The person gets a bonus of $6,200 during Christmas.

96,600 - 6,200 = 90,400

The person earns $90,400 yearly.

[tex]\frac{90,400}{12}[/tex] = 7,533.3333

Each month, the person earns $7,533.33, to the nearest cent.

Answer:

Q1= 2, Q2 = 4.5, Q3 = 7.5

Step-by-step explanation:

firstly, put the data is other;

0 1 1 1 2 2 2, 2 2 3 3 4 4 4, 5 6 7 7 7 7 7, 8 8 8 8 8 8 9

the Q1 = (2+2)/2 = 2

Q2 = (4 + 5)/ 2 = 4.5

Q3 = (7 + 8)/2 = 7.5

Answer:

The answer is 1/14w-8

Answer and Step-by-step explanation:

This is a complete question

Trials in an experiment with a polygraph include 97 results that include 23 cases of wrong results and 74 cases of correct results. Use a 0.01 significance level to test the claim that such polygraph results are correct less than 80​% of the time. Identify the null​hypothesis, alternative​ hypothesis, test​ statistic, P-value, conclusion about the null​ hypothesis, and final conclusion that addresses the original claim. Use the​ P-value method. Use the normal distribution as an approximation of the binomial distribution.

The computation is shown below:

The null and alternative hypothesis is

[tex]H_0 : p = 0.80[/tex]

[tex]Ha : p < 0.80[/tex]

[tex]\hat p = \frac{x}{ n} \\\\= \frac{74}{97}[/tex]

= 0.7629

Now Test statistic = z

[tex]= \hat p - P0 / [\sqrtP0 \times (1 - P0 ) / n][/tex]

[tex]= 0.7629 - 0.80 / [\sqrt(0.80 \times 0.20) / 97][/tex]

= -0.91

Now

P-value = 0.1804

[tex]\alpha = 0.01[/tex]

[tex]P-value > \alpha[/tex]

So, it is Fail to reject the null hypothesis.

There is ample evidence to demonstrate that less than 80 percent of the time reports that these polygraph findings are accurate.

Answer:

y=3

Step-by-step explanation:

-5y+8=-7

Minus 8 from each side.

-5y=-15

Divide -5 from each side.

y=3