A consumer group is testing camp stoves. To test the heating capacity of a stove, they measure the time required to bring 2 quarts of water from 50 degrees to boiling.
Two competing models are under consideration. Thirty-six stoves of each model were tested and the following results were obtained.
Model 1: mean time is 11.4 and standard deviation is2.5
Model 2: mean time is 9.9 and standard deviation is 3.0
Is there any difference between the performances of these two models? {use a .05 level of significance}. Find the p-value of the sample statistic and do a significance test.
Find a 95% confidence interval for the difference of the means.

Answers

Answer 1

Answer:

a

The decision rule  is  

Reject the null hypothesis

  The conclusion is  

There is sufficient evidence to show that there is a difference between the performances of these two models

b

The  95% confidence interval is  [tex] 0.224   <  \mu_1 - \mu_2  < 2.776  [/tex]

Step-by-step explanation:

From the question we are told that

    The sample size is  n  =  36

    The first sample mean is  [tex]\= x_1 = 11.4[/tex]

    The first standard deviation is  [tex]s_1 = 2.5[/tex]

    The second sample mean is   [tex]\= x_2 = 9.9[/tex]

     The second standard deviation is  [tex]s_2 = 3.0[/tex]

      The level of significance is  [tex]\alpha = 0.05[/tex]

The null hypothesis is  [tex]H_o : \mu_1 - \mu_2 = 0[/tex]

The alternative hypothesis is [tex]H_a : \mu_1 - \mu_2 \ne 0[/tex]

Generally the test statistics is mathematically represented as

      [tex]z = \frac{ (\= x_1 - \= x_2 ) - (\mu_1 - \mu_2 ) }{ \sqrt{ \frac{s_1^2 }{n} + \frac{s_2^2 }{ n} } }[/tex]

=>    [tex]z = \frac{ ( 11.4 - 9.9) - 0 }{ \sqrt{ \frac{2.5^2 }{36} + \frac{ 3^2 }{36 } } }[/tex]

=>     [tex]z = 2.3[/tex]

From the z table  the area under the normal curve to the left corresponding to  2.3 is  

       [tex]P( Z > 2.3 ) = 0.010724[/tex]

Generally the p-value is mathematically represented as

      [tex]p-value = 2 * P( Z > 2.3 )[/tex]

=>    [tex]p-value = 2 * 0.010724[/tex]

=>    [tex]p-value = 0.02[/tex]

From the value obtained we see that  [tex]p-value < \alpha[/tex] hence  

The decision rule  is  

Reject the null hypothesis

  The conclusion is  

There is sufficient evidence to show that there is a difference between the performances of these two models

Considering question b

From the question we are told the confidence level is  95% , hence the level of significance is    

      [tex]\alpha = (100 - 95 ) \%[/tex]

=>   [tex]\alpha = 0.05[/tex]

Generally from the normal distribution table the critical value  of  [tex]\frac{\alpha }{2}[/tex] is  

   [tex]Z_{\frac{\alpha }{2} } =  1.96[/tex]

Generally the margin of error is mathematically represented as  

      [tex]E = Z_{\frac{\alpha }{2} } *  \sqrt{ \frac{s_1^2 }{n } + \frac{s_2^2}{n}} [/tex]

 => [tex]E = 1.96  *    \sqrt{ \frac{2.5^2 }{ 36 } + \frac{ 3^2}{36}}  [/tex]

  => [tex]E = 1.276   [/tex]

Generally 95% confidence interval is mathematically represented as  

      [tex]( \= x_1 - \= x_2) -E <  \mu_1 - \mu_2  < ( \= x_1 - \= x_2) + E [/tex]

=>  [tex]( 11.4 - 9.9 ) -1.276  <  \mu_1 - \mu_2 < ( 11.4 - 9.9 ) + 1.276   [/tex]

=>  [tex] 0.224   <  \mu_1 - \mu_2  < 2.776  [/tex]


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5 cans need to be bought. There are three servings in each can so you divide 15 by 3.

Answer:

5 cans need to be bought

Step-by-step explanation:

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Simplify expression (distributive property) 11(9+d) if correct I'll mark brainliest!

Answers

11 x 9 is 99 so then you do 11 x d and that’s 11d so it would be 99+11d :)

Answer After Distributing: 99 + 11d

Work: You multiply 9 and d by 11, and you get 99 + 11d.

I hope this helps, and Happy Holidays! :)

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Answers

Answer:

x=30

Step-by-step explanation:

set the sum of both equal to 180 bc it makes a straight line

(x-1)+(5x+1)=180

add and subtract 1 from each side

x+5x=180

add like terms

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divide by 6

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Answer:

D: x=30

Step-by-step explanation:

(x-1)⁰+ (5x+1)⁰=180⁰

x-1+5x+1=180

x+5x-1+1=180

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Answers

Answer:

4

Step-by-step explanation:

..............................

Please help and explain how you got the answer. Im giving out brainliest. || Q2

Answers

Answer:

B

Step-by-step explanation:

Convert 3/5 and each fraction so that that they have the same denominator by finding the (lowest) common multiple. If they have the same numerator, then the fractions are equivalent.

Whatever you multiply the denominator by, you need to multiply the numerator by.

A) The lowest multiple of 5 and 15 is 15.

5 * 3 = 15

3 * 3 = 9

3/5 = 9/15

B) The lowest multiple of 5 and 16 is 80.

5 * 16 = 80

3 * 16 = 48

3/5 = 48/80

16 * 5 = 80

12 * 5 = 60

C) The lowest multiple of 5 and 50 is 50.

5 * 10 = 50

3 * 10 = 30

3/5 = 30/50

D) The lowest multiple of 5 and 60 is 60.

5 * 12 = 60

3 * 12 = 36

3/5 = 36/60

Apply the distributive property to convert the expression to the greatest common factor multiplied by a term in parenthesis.

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Answers

Answer:

9(4a+1)=

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7(4-f)=

Step-By-Step Solution:

The greatest common factor is the largest number that both numbers can be divided by. For example, in #1, 36 and 9 can both be divided by 9 to become 4 and 1.

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Answers

Answer:

When two triangles are similar, the reduced ratio of any two corresponding sides is called the scale factor of the similar triangles.

Step-by-step explanation:

Theorem 60: If two similar triangles have a scale factor of a : b, then the ratio of their perimeters is a : b.

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Answers

Answer:

Doesn't this mean that 592 students live outside the city of mansfield?

Step-by-step explanation:

800 - 208

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Answers

Answer:

(-6,0) is not a solution

A meteorologist predicted that there would be 1.0 inches of rainfall from a storm. Instead, there were 2.2 inches of rainfall. Which statements are true?

a
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b
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c
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d
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Answers

Answer:

pls write the question clearly

Step-by-step explanation:

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The statements that is true: B. The percent error of the prediction was about 55%.

D. Difference between the predicted and actual rainfall was 1.2 inches.

What is the percentage error?

Percentage error can be calculated  using this formula;

Percentage error = Actual value observed - Expected value /Expected value

The Percentage error is;

= 2.2 - 1.0 / 2.2

Percentage error = 1.2 /2.2

Percentage error = 0.545 × 100

Percentage error = 55% (Approximately)

Since Difference between the predicted and actual rainfall;

Difference = Actual rainfall - Predicted rainfall

Difference = 2.2 -1.2

Difference = 1.2 inches.

Hence the correct statement is option B and D.

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Randy saving for console cost $290 he got a $50 gift card from grandma $15 each week, how many weeks until he get money?

Answers

Answer:

it will take him 16 weeks

Step-by-step explanation:

290 subtract 50 equals 240

240 divided by 15 equals 16

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Answers

I think it’s a.........

Sam's height= 1.58m

Tom's height= 0.4m less than Sam's

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Answers

Answer:

          8 cm

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Step-by-step explanation:

Moving from point (0, 0) to point (5, 8), we see that the x-coordinate (the 'run') increases by 5 wk and the y-coordinate (the 'rise') increases by 8 cm.  Thus we have the rate of change

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Answers

Answer:

How many hamburgers were sold on Sunday?

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Answers

Answer:

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Step-by-step explanation:

2x2-40x33 divided by 2 and boom answer 500

Anser:

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Step-by-step explanation:

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Answer:picture?

Step-by-step explanation:

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Answer:

i think its 24 because its the alternate exterior so it should be the same.

Step-by-step explanation:

Answer:

24

Step-by-step explanation:

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Discontinuous if I’m not mistaken

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Answer:

4.3890563e+45!!

Step-by-step explanation:

A weather balloon is released and rises vertically such that its distance s (t) above the ground during the first 10 sec of flight is given by s(t)-6+2t+t2, where s(t) is in feet and t is in (a) Find the velocity at t- 4 seconds. (Worth 5 points) sec/Pt Answer (b) Find the instant the balloon is 50 feet above the ground.

Answers

Step-by-step explanation:

A weather balloon is released and rises vertically such that its distance s (t) above the ground during the first 10 sec of flight is given by :

[tex]s(t)=6+2t+t^2[/tex] ...(1)

(a) We need to find velocity at t = 4 seconds

Differentiate equation (1) wrt t.

[tex]v=\dfrac{ds}{dt}\\\\v=\dfrac{d(6+2t+t^2)}{dt}\\\\v=2+2t[/tex]

At t = 4 seconds,

[tex]v=2+2(4)\\\\=10\ ft/s[/tex]

At t = 4 seconds, the velocity is 10 ft/s.

(b) When the balloon is 50 feet above the ground,

[tex]6+2t+t^2=50[/tex]

We need to find t.

[tex]6+2t+t^2=50\\\\t^2+2t-50+6=0\\\\t^2+2t-44=0[/tex]

It is a quadratic equation,

t = 5.708 and t = -7.708

Neglecting negative time, the instant time is 5.708 seconds.

pls help having a hard time understanding I just need the answers

Answers

Answer:

B

Step-by-step explanation:

Basically, you can rule out all of the other answers by the following criteria:

A is wrong because any y= equation without an x is just a straight horizontal line

C is wrong because any x= equation is just a vertical line

D is wrong because both lines shown are positive lines, and both equations in  answer D are negative

Therefore by process of elimination, the only answer that makes sense is B


Refer to - KLMN •
3r
M
2y
3 cm
ס
60°
K
N
x + 4 cm
What is the length of LM in cm?

Answers

Answer:

[tex]LM = 6cm[/tex]

Step-by-step explanation:

[tex]LM = KN[/tex]

[tex]3x =x + 4[/tex]

[tex]3x - x = 4[/tex]

[tex]2x = 4[/tex]

[tex] \frac{2x}{2} = \frac{4}{2} [/tex]

[tex]x = 2[/tex]

then

[tex]LM = 3x[/tex]

[tex]LM =3 \times 2[/tex]

[tex]LM = 6cm[/tex]

The height in feet (h) of the ball t seconds after it is released can
be modeled using the formula: – 16t^2 + 10t + 6 = h
Find the time, in seconds, passed before the ball hits the ground
(let h = 0).*
*PLEASE SHOW WORKK

Answers

Step-by-step explanation:

h = -16t² + 10t + 6

When h = 0, -16t² + 10t + 6 = 0.

=> -8t² + 5t + 3 = 0

=> (-8t - 3)(t - 1) = 0

=> t = 1 or t = -3/8 (rejected as time cannot be negative)

Hence 1 second passed before the ball hits the ground.

Draw a scaled copy of the circle
using a scale factor of 2.

How does the circumference of the scaled copy compare to the circumference of the original circle?
How does the area of the scaled copy compare to the area of the original circle?

Answers

Answer:

the circumfrence is the diameter times pi so if the diameter was 3 you would time that by 3.14 to get the circumfrence hope that helps

Step-by-step explanation:

The circumference of the scaled copy is half the circumference of the original circle.

The area of the scaled circle is half the area of the original circle.

What is a scale factor?

A scale factor is defined as the ratio between the scale of a given original object and a new object,

We have,

Let the radius of the circle = r

The circumference of the circle = 2πr

The area of a circle = πr²

Now,

Scale factor = Original circle / Scaled circle

Now,

Scale factor = 2

2 = Circumference of the Original circle / Circumference of the Scaled circle

Circumference of the Scaled circle = (1/2) Circumference of the Original circle

Again,

Scale factor = 2

2 = Area of the Original circle / Area of the Scaled circle

Area of the scaled circle = (1/2) Area of the original circle

Thus,

The circumference of the scaled copy is half the circumference of the original circle.

The area of the scaled circle is half the area of the original circle.

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pls help! will give brainliest!!!

Answers

Answer:?????

Step-by-step explanation:

what do u need help with/?//???/???

What’s the question? It’s not there

Find the x-intercept and y-intercept of the line given by the equation below. Then graph the line.
x + y = 2
X-intercept:
y-intercept:

Answers

y-intercept: (0,2)
x-intercept: (2,0)

graphed:
Y intercept: 0,2)

X intercept (2,0)

Solve the equation for x. 25x = 275

x =​

Answers

Answer:

x = 11

Step-by-step explanation:

So the equation is  25x = 275. In order for us to find out what x is we need to get rid of 25 that is next to x, so we are going to have to divide 25x by 25. What you do to one side you do to the other so the equation will look like this:

25x/ 25 = 275/ 25

25x/25 = x

275/25 = 11

so x = 11

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