The Rockwell hardness index for steel is determined by pressing a diamond point into the steel and measuring the depth of penetration. For 50 specimens of an alloy of steel, the Rockwell hardness index averaged 62 with standard deviation 8. The manufacturer claims that this alloy has an average hardness index of at least 64. Is there sufficient evidence to refute the manufacturer’s claim at the 1% significance level?

Answers

Answer 1
Does it say anything about carbon?

Related Questions

a manned rocket accelerates at a rate of 20 m/s2 during launch How long does it take the rocket reach a velocity of 400 m/s?

Answers

Answer:

Step-by-step explanation:

acceleration, a = 20 m/s^2

initial velocity, u = 0 since it starts from rest

final velocity, v = 400 m/s

v = u + at

400 = 0 + 20 t

400 = 20 t

t = 400 / 20

t = 20 sec

Hope this helps

plz mark as brainliest!!!!

It will take 20 sec the rocket reach a velocity of 400 m/s

What are equations of motion?

There are three equation of motions that can be used when motion of the object is under constant acceleration and on a straight path.

They are listed below as:

[tex]v = u + at\\\\s = ut + \dfrac{1}{2} at^2\\\\v^2 = u^2 + 2as[/tex]

We are given that manned rocket accelerates at a rate of 20 m/s2 during launch

The acceleration, a = 20 m/s^2

The initial velocity, u = 0 since it starts from rest

The final velocity, v = 400 m/s

Therefore, v = u + at

400 = 0 + 20 t

400 = 20 t

t = 400 / 20

t = 20 sec

Hence, It will take 20 sec the rocket reach a velocity of 400 m/s

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Solve 4(p - 15)=312 please

Answers

Answer:

p = 93

Step-by-step explanation:

4(p - 15)=312

4p - 60 = 312

4p - 60 + 60 = 312 + 60

4p = 372

4p/4 = 372/4

p = 93

Answer:

the answer is 93......

The area of a square mirror is 196 in. A rectangular
mirror has a width the same as the square mirror's
width. Its length is two inches longer than its width
What is the area of the rectangular mirror?

Answers

Answer:

rectangle=224 in^2

Step-by-step explanation:

the square is 14x14 coz the square root of 196=14

the rectangles length is 2 inches longer so its 14x16

14x16=224

What is the greatest common factor of 36, 34, and 22?

Answers

factors of 36: 1,2,3,4,6,9,12,18,36
factors of 34: 1,2,17,34
factors of 22: 1,2,11,22
GCF: 2

We have that the factors of the individual Number  

(1,2,3,4,6,9,12,18,36),( 1,2,17,34),(  1,2,11,22 ) respectively

The greatest common factor is 2

2

From the question we are told

What is the greatest common factor of 36, 34, and 22?

Generally the equation for the Factors  is mathematically given as

36 factors are as follows 1,2,3,4,6,9,12,18,36

34 factors  factors are as follows  1,2,17,34

22 factors factors are as follows   1,2,11,22

Therefore

From the factors of the individual Number  

(1,2,3,4,6,9,12,18,36),( 1,2,17,34),(  1,2,11,22 ) respectively

The greatest common factor is 2

2

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Please helppppppppppppp

Answers

Answer:

the 5th diagram illustrates

AB has endpoints at (-4,5) and (4,-3) using the midpoint formula what is the midpoint segment

Answers

Answer:

(0,1)

Step-by-step explanation:

3(3a - 5b) - (a - 76)

Answers

Answer:

8a-15b+76

Step-by-step explanation:

that is the answer

The environmental science club is printing T-shirts for its 15 members. The printing company charges a certain amount for each shirt plus a setup fee of $20.



If the T-shirt order costs a total of $162.50, how much does the company charge for each shirt?

Answers

Answer:

x=9.5

Step-by-step explanation:

Let  be the cost of each shirt. From the information provided in the problem, we can setup the following equation:

Solving for  will give us the answer:

GG

is angle 2 in the diagram and angle of elevation or an angle of depression​

Answers

Answer:

Angle of elevation

Step-by-step explanation:

An angle measured from the horizontal upwards is an angle of elevation.

An angle measured from the horizontal downwards is an angle of depression.

∠ 2 is a measure from the horizontal upwards thus angle of elevation.

Note that ∠ 3 is an angle of depression

For the following questions, solve for the missing rate, base or product (round to the nearest hundredth if needed): 25% of 320 is

Answers

Answer:

80

Step-by-step explanation:

let the unknown value be x.

[tex]\frac{25}{100}*320=x\\ \frac{25*320}{100}=x\\ \frac{8000}{100}=x\\ 80=x[/tex]

Answer:

[tex]\huge\boxed{80}[/tex]

Step-by-step explanation:

[tex]25 \% \ of \ 320[/tex]

% means out of hundred and of means to multiply.

=> [tex]\\\frac{25}{100} * 320\\[/tex]

=> 0.25 * 320

=> 80

how do you add integers with the same sing​

Answers

Use this method it on the pg number 125 of ncert book

Answer:

For example

-10+(-2)

=-10-2

=-12

Step-by-step explanation:

hope this helps you ☺️

If yes then do mark my answer as brainliest

Find ????⋅ ???? if |????|=3 , |????|=9 , and the angle between ???? and ???? is π2 radians.
a.b = _______

Answers

Answer:

[tex]a{\cdot}b=0[/tex]

Step-by-step explanation:

It is given that,

Magnitude of a A, [tex]|A|=3[/tex]

magnitude of B, [tex]|B|=9[/tex]

The angle betwern a and b is [tex]\dfrac{\pi}{2}\ rad=90^{\circ}[/tex]

Dot product,

[tex]a{\cdot} b=|a||b|\ \cos\theta\\\\a{\cdot} b=3\times 9\times \ \cos(90)\\\\a{\cdot} b=0[/tex]

So, a.b is equal to 0.

Find the Product. 437 × 16​

Answers

Answer: [tex]6692[/tex]

Look at the image for work...

Divide 3/12 divide 9

Answers

Answer:

[tex]\frac{7}{18}[/tex]

Step-by-step explanation:

Convert 3 1/2 to a mixed number. It should now look like this: 7/2Write out the new expression: [tex]\frac{7}{2}[/tex] ÷ [tex]\frac{9}{1}[/tex]  Multiply by the reciprocal of 9/1: [tex]\frac{7}{2}[/tex] × [tex]\frac{1}{9}[/tex] = [tex]\frac{7}{18}[/tex]

Answer:

7/18

Step-by-step explanation:

round these numbers to the nearest tenth 2.65 and 159.39

Answers

2.7 and 158.4 ...........

Answer: 2.7  and 159.4

Step-by-step explanation:

To round numbers tot he nearest tenth,check their tenth digit and if the next number that comes before it is equal or greater than 5, then round that tenth digit up by 1.  

The number  2.65  , number 6  is in the tenth place and the number next to it which is 5 is in the hundredths place so to to the nearest tenth will be  2.7  .

The second number 159.39  the tenth place digit is 3 and the number next to it is greater than 5 so after rounding you will get  159.4

Question 1 Create Triangle ABC by drawing AC AC represents the foreman’s line of sight to the top of the landfill. What is Angle m BAC?

Answers

The required angle m BAC = 45°.

In triangle ABC.
AC represents the foreman’s line of sight to the top of the landfill.
Landfill height is =BC

What is triangle?

The triangle is geometric shape which includes 3 sides and sum of interior angle should not grater than 180°

According to conditions angle b = 90°

The sum of angles of a triangle= 180°

That is a + b + c = 180

Therefore, c = a
        a = (180 - b)/2

           = (180 - 90) / 2
           = 90 / 2
           = 45 degrees.

Thus, the required angle m BAC = 45°


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Answer:

m BAC = 35°

Step-by-step explanation:

Can anyone help me find the value pls?

Answers

The inside angle for B, which is labeled x is the same as the outside angle of D which is labeled as 72, so we know x = 72.

In a parallelogram two angles next to each other equal 180, so angle A and angle B equal 180.

We know B = 72, so A = 180-72 = 108

Angle A is divided in 2 by angle y, so y = 108/2 = 54

Answers: x = 72

Y = 54

help me pleasee (and no I’m not gonna follow u if u ask just help)

Answers

Answer:

option B is correct -7 is the answer

Step-by-step explanation:

=4⁴-3³.(12-3)-20

=256-27×(9)-20

=256-243-20

=256-263

=-7

hope it will help ^_^

Answer:

[See Below]

Step-by-step explanation:

First you'll solve the parenthesis part:

* 12 - 3 = 9

Then Solve the exponents:

* 4^4 = 256 (4 x 4 x 4 x 4)

* 3^3 = 27 (3 x 3 x 3)

Rewrite:

* 256 - 27 x 9 - 20

Multiply:

* 27 x 9 = 243

Subtract:

* 256 - 243 = 13

* 13 - 20 = -7

So the answer would be B, -7

(Remember to use PEMDAS to solve)

Todd is traveling to Mexico and needs to exchange $400, in US dollars, into Mexican pesos. If each dollar is worth 12.29 pesos, how many pesos will he get for his trip?

Answers

Answer:

4916 pesos

Step-by-step explanation:

Olivia deposited $2,136.70 into a saving account with an interest rate of 2.7% compounded quarterly. About how long will it take for the account to be worth $4,000?

Answers

Answer:

23.3 years

Step-by-step explanation:

4000 = 2136.7(1 + .027/4)^(4t)

4000 / 2136.7 = 1.00675^4t

ln (4000 / 2136.7) / ln 1.00675^4 = t

23.301690290541729158877031400229 = t

23.3 years

Answer:

23.26 years

Step-by-step explanation:

Use the compound interest formula:

A = P [tex]( 1 + \frac{r}{100n} )^{nt}[/tex]

A =  final amount

P =  initial principal balance

r =  interest rate

n =  number of times interest applied per time period

t =  number of time periods elapsed

P = $2,136.70

r = 2.7

n = 4

A = $4,000

Now we plug everything in and solve for t.

$4,000 = $2,136.70 [tex](1 + \frac{2.7}{100 * 4} )^{4t}[/tex]

$4,000 = $2,136.70 [tex](1 + .00675 ) ^{4t}[/tex]

$4,000 = $2,136.70[tex](1.00675)^{4t}[/tex] Divide each side by $2,136.70

$4,000/$2,136.70 = [tex](1.00675)^{4t}[/tex]

1.87 = [tex](1.00675)^{4t}[/tex]

log (1.87) = log [tex](1.00675)^{4t}[/tex]

log 1.87 = (4t) (log 1.00675)  Divide each side by (log 1.00675)

[tex]\frac{log 1.87}{log 1.00675}[/tex] = 4t

93.044 = 4t Divide each side by 4.

93.044/4 = t

23.26 = t

23.26 years

ay = b - 2a
how do i solve this step by step?

Answers

Answer:

[tex]a = \frac{b}{2+ y}[/tex]

Step-by-step explanation:

Given

[tex]ay = b- 2a[/tex]

Required

Solve for a

[tex]ay = b- 2a[/tex]

Add 2a to both sides

[tex]2a + ay = b- 2a + 2a[/tex]

[tex]2a + ay = b[/tex]

Factorize

[tex]a(2 + y)= b[/tex]

Divide through by 2 + y

[tex]a = \frac{b}{2+ y}[/tex]

Answer:

a = b/(y + 2)

Step-by-step explanation:

Solve for a:

a y = b - 2 a

Hint: | Isolate a to the left hand side.

Add 2 a to both sides:

a (y + 2) = b

Hint: | Solve for a.

Divide both sides by y + 2:

Answer: a = b/(y + 2)

In the exam 45% students failed and 550 students were successful. The total number of students appeared in the exam.

Answers

Answer:

1000

Step-by-step explanation:

a population has a mean of 25 median of 24 and mode of 26 the standard deviation is 5 the value for the

Answers

Complete Question

A population has a mean of 25, a median of 24, and a mode of 26. The standard deviation is 5. The value of the 16th percentile is _______. The range for the middle 3 standard deviation is _______.

Answer:

The  value  of the 16th percentile  is  [tex]x = 20[/tex]

The range for the middle 3 standard deviation is  [tex]10 \to 40[/tex]

Step-by-step explanation:

From the question we are told that

     The  mean is  [tex]\mu  =  25[/tex]

     The  median is  [tex]m  =  24[/tex]

     The  mode is  [tex]n =  26[/tex]

     The  standard deviation is  [tex]\sigma  =  5[/tex]

Generally the 16th percentile is mathematically represented as

  [tex]P(x)= P(\frac{X  -  \mu }{ \sigma }   \le \frac{x- 25 }{5} ) = 0.16[/te

Generally  [tex]\frac{X -  \mu}{\sigma }  =  Z(The  \  standardized \  value \ of  \ X  )[/tex]

So

       [tex]P(x) =  P(Z \le \frac{ x -  25}{5} ) =  0.16[/tex]

Now from the normal distribution table  the z-score of  0.16 is  

      z =  -1

       [tex]P(x) =  P(Z \le \frac{ x -  25}{5} ) =  P(Z \le -1 )[/tex]

=>  [tex]\frac{x- 25}{5}  =  -1[/tex]

=>    [tex]x- 25  =  -5[/tex]

=>      [tex]x =  25-5[/tex]

=>       [tex]x = 20[/tex]

The range for the middle 3 standard deviation is mathematically represented

        [tex]\mu  -  3\sigma \to \mu + 3\sigma[/tex]

        [tex]25 -  3(5 ) \to 25 +  3(5 )[/tex]

         [tex]10 \to 40[/tex]

 

   

what is (5x-2)(4x^2 -3x-2)

Answers

Answer: 20x^3 - 23x^2 - 4x + 4

Explanation:

Use distributive property:

(5x-2)(4x^2 - 3x-2)
= 20x^3 - 15x^2 - 10x - 8x^2 + 6x + 4
= 20x^3 - 23x^2 - 4x + 4

Answer:

20x^3-23X^2-4X+4

Step-by-step explanation:

Data accumulated by the National Climatic Data Center shows that the average wind speed in miles per hour for St. Louis,Missouri, is 9.7. Suppose wind speed measurements are normally distributed for a given geographic location. If 22.45% of the time the wind speed measurements are more than 11.6 miles per hour, what is the standard deviation of wind speed in St. Louis?

Answers

Answer:

The  value is  [tex]\sigma = 8.5[/tex]    

Step-by-step explanation:

From the question we are told that

  The  population mean is  [tex]\mu = 9.7[/tex]

   The  proportion is  [tex]P(X >x) = 0.2245[/tex]

   The value considered is  [tex]x = 11.6[/tex]

Generally given that the speed measurement is normally distributed we have that

   [tex]P(X > 11.6) = P(\frac{ X - \mu }{ \sigma } > \frac{11.6 - 9.7}{ \sigma } ) = 0.2245[/tex]

Generally

   [tex]\frac{X - \mu}{ \sigma } = Z(The \ z -score \ of \ X )[/tex]

[tex]P(X > 11.6) = P(Z> \frac{11.6 - 9.7}{ \sigma } ) = 0.2245[/tex]

Hence

     [tex]\frac{ 11.6 - 9.7}{ \sigma} = 0.2245[/tex]

  [tex]\sigma = 8.5[/tex]      

It is 185 miles to fort worth. If vang drives 2hours at 65 mph, how far will he be from fort worth?

Answers

Answer:

185-65÷2=120 that the answer

Answer:

55 miles

Step-by-step explanation:

d= 185 - 2*65

d=185 - 130

d= 55 miles

Find the distance between these points.

C(0, 4), T(-6, -3)

√(37)
√(109)
√(85)

Answers

Hey there! I'm happy to help!

To find the distance between two points, you find the difference between the y and x values, square them, add them, and then find the square root of that.

We subtract our y values.

-3-4=-7

And then our x values.

-6-9=-6

We square these values.

-7²=49

-6²=36

We add these.

49+36=85

And we find the square root, giving us √85.

Have a wonderful day! :D

Answer:

√85.

Hopefully this helps a bit, I don't really understand math much, but when I calculated, this is what I got:

Step-by-step explanation:

Subtract your y values.

-3-4=-7

And then your x values.

-6-9=-6

You square these values.

-7²=49

-6²=36

You add these.

49+36=85

And you find the square root, giving you √85

4b + 11 + 8b + 1 = 180

Answers

Answer:

b=14

Step-by-step explanation:

Add 4b and 8b, which you get 12b. Then you add 11 and 1 which you get 12.

12b + 12 = 180 is the next equation.

Afterwards, you subtract 12 from 180.

12b = 168

Divide 12b from 168.

b = 14

Find for B?

Mk in this equation

4b + 11 + 8b + 1 = 180

Subtract 11 and 1 from both sides

4b + 8b = 168

Combine unknowns

12b = 168

Find b by dividing by 12

Thus, B = 14

Hope this helps,

Jeron

P.S, if you found this really helpful, consider marking brainliest, (you don't have to btw)

What guides a researcher when deciding between using either linear, logistic, or Cox proportional hazards regression as an analysis tool

Answers

Answer:

The outcome variable type (continuous, binary, or time -to- event)

Explanation:

The outcome variable type is the type of variables involved in a research. The researcher would put the type of variable involved in his research into consideration in deciding what regression model to apply in his research. For example, if the type of variable in his research are continuous variables(continuous variables are variables that may be any value within a range and may be infinite), he would use linear regression

The outcome variable type for the particular analyses utilizing the regression model.

When determining a regression model that can be used in his experiment or investigation, perhaps the researcher needs to examine the type of classification concerned.Like, the numbers or scores a person receives on a test are the product of hard work assessed in the total hours spent studying and intellect evaluated in IQ, which has been independent factors.

Thus the response above is correct.

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Which symbols correctly relates the 2 numbers 55?35

Answers

Answer:

>

Step-by-step explanation:

55 is greater than 35, so the open "mouth" of the greater than sign should go towards 55.

Answer:

>

Step-by-step explanation:

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