The manager of a fleet of automobiles is testing two brands of radial tires and assigns one tire of each brand at random to the two rear wheels of eight cars and runs the cars until the tires wear out. The data (in kilometers) follow. Find a 99% confidence interval on the difference in the mean life.
Car Brand 1 Brand 2
1 36663 33866
2 43509 41829
3 36240 35500
4 32100 31950
5 37210 38015
6 48360 47800
7 38200 37810
8 33500 33215
a) Calculate SD =
b) Calculate a 99% two-sided confidence interval on the difference in mean life.
c) Which brand would you prefer? (brand 1/ no difference /brand 2)_____

Answers

Answer 1

Answer:

a) σ  =  4933,64

b) CI 99%  = ( - 5746  ;  7194 )

c) No difference in brands

Step-by-step explanation:

Brand 1:

n₁   =  8

x₁   = 38222

s₁   = 4974

Brand 2:

n₂  = 8

x₂  = 37498

s₂  = 4893

As n₁  =  n₂  = 8       Small sample  we work with t -student table

degree of freedom      df  = n₁  +  n₂  - 2    df = 8 +8 -2  df = 14

CI = 99 %   CI  =  0,99

From  t-student table we find   t(c)  = 2,624

CI  =   (  x₁  -  x₂ ) ±  t(c) * √σ²/n₁   +  σ²/n₂

σ² = [( n₁  -  1 ) *s₁² +  ( n₂  -  1  ) * s₂² ] / n₁ +n₂ -2

σ² = 7* (4974)² + 7*( 4893)² / 14

σ² = 24340783       σ  =  4933,64

√ σ²/n₁  +  σ²/n₂     =  √ 24340783/8   +  24340783/8

√ σ²/n₁  +  σ²/n₂     =  2466

CI 99%  =  (  x₁  -  x₂ ) ± 2,624* 2466

CI 99%  =   724  ± 6470

CI 99%  = ( - 5746  ;  7194 )

As we can see CI 99% contains 0 and that means that there is not statistical difference between mean life of the two groups


Related Questions

1. Force is a push or a
upon an object
A heat
C. pull
B. motion
D. transfer
2 Which is needed to make an object move?
A density
C. porous
B. force
D. non-porous

Answers

Answer:

1. C

2.B

Step-by-step explanation:

Force is a push or a pull.. can be a twist too

to make an object move you have to apply force by pushing of pulling the object.

No me voy al hospital a la oficina porque yo no tengo ni caso de la casa ni siquiera te quiero mucho

32614 round to nearest 100 place?​

Answers

Answer:

32600

Step-by-step explanation:

32700 would be the answer

work out the value of (6-2.5)( 8+4)​

Answers

Answer:

42

Step-by-step explanation:

Uh, I'm guessing what is being asked here is to solve, so, time to distribute.

(6 - 2.5)(8 + 4)

48 + 24 - 20 - 10

42

A pair of weak earthquakes is modeled by a system of inequalities. One earthquake occurred roughly 20 km east and 14 km north of the center of Columbia, NC. The quake could be felt from 25 km away. A couple days later, another earthquake occurred 8 km west and 3 km north of the center of Columbia and could be felt from 14 km away. If Columbia is located at (0, 0) on a coordinate grid, the system of inequalities represents this scenario.

StartLayout Enlarged left-brace first row (x minus 20) squared + (y minus 14) squared less-than-or-equal-to 625 second row (x + 8) squared + (y minus 3) squared less-than-or-equal-to 196 EndLayout

Which location relative to Columbia felt both earthquakes?

4 km west and 12 km south
6 km west and 4 km north
2 km east and 10 km north
6 km east and 8 km north

Answers

Answer:

2 km east and 10 km north

Step-by-step explanation:

I did the activity and got the right answer.

By evaluating the inequalities, we will see that the correct option is: 2 km east and 10 km north

Which location will feel both earthquakes?

Here we have the inequalities:

(x - 20)^2 + (y - 14)^2 ≤ 625

(x + 8)^2 + (y - 3)^2 ≤ 196

Where, x is the distance due east, and y is the distance due north.

So we just need to find which of the given options makes both inequalities true, for example, for the first one we have:

x = -4

y = -12

Replacing that on the first inequality we get:

(-4 - 20)^2 + (-12 - 14)^2 ≤ 625

1,252 ≤ 625

This is false, so this option is not correct.

Now we just need to check the other options. Particularly for the third we have:

x = 2

y = 10

Replacing that in both inequalities we get:

(2 - 20)^2 + (10 - 14)^2 ≤ 625

340 ≤ 625 (true).

(2 + 8)^2 + (10 - 3)^2 ≤ 196

149 ≤ 196 (true)

So at 2km east and 10km north of Columbia, the two earthquakes can be felt.

If you want to learn more about inequalities, you can read:

https://brainly.com/question/18881247

Product of ²/₇ with the reciprocal of ⁽⁻³⁾/₈ is​

Answers

Answer:

Step-by-step explanation:

Reciprocal of (-3)/8 = -8/3

[tex]\frac{2}{7}*\frac{-8}{3}=\frac{2*(-8)}{7*3}=\frac{-16}{21}[/tex]

multiplying and simplify radicals!

if u get it right I’ll give brainliest (show work pls!!!)

Answers

Answer: 8

Explanation: To multiply two square roots together, simply multiply the numbers inside the square roots together to get [tex]\sqrt{64}[/tex] which is 8.

Notice that when you multiply a square root times itself, the radical disappears, and you're left with the number inside the original square root.

Kerry puts pennies into a jar every day. On the first day, she puts 2 pennies into the jar. On the second day, she adds double the number of pennies she put into the jar on the first day. On the third day, she adds double the number of pennies she put into the jar on the second day. This pattern follows for a week.

Answers

Answer:

By the end of the week she will have 254 pennies and she will put 128 pennies for the last day

y = x2 – 3x + 2
use the discriminant to determine the number of solutions​

Answers

Answer:

2 real solutions

Step-by-step explanation:

The formula for determining the discriminant is b² - 4ac.

So, let's identify our variables.

a = 1

b = 3

c = 2

Now, we can plug in our values.

3² - 4(1)(2)

9 - 8

1

1 is the discriminant of this function, and since 1 is positive, this indicates that there are two distinct real number solutions.

Mj3mar gave the answer thanks to him I wouldn’t have got my question right

what is the following product?
square root of 30 times the square root of 10

Answers

Step-by-step explanation:

That 'd be the square root of 300, which is equivalent to 10sqrt(3).

Help me find the value of x plss

Answers

Answer:

Generally, the algebraic expression should be any one of the forms such as addition, subtraction, multiplication and division. To find the value of x, bring the variable to the left side and bring all the remaining values to the right side. Simplify the values to find the result.

Answer:

What do we see in triangle -- adj and hyp

cosine since it is SOH CAH TOA

cos(14)/1 =x/480

Answer = 465.74 the real rounding is 466

She mixes nuts, raisins and oats in the ratio 3:2:5 by weight. Babajan uses 60 grams of nuts. Work out the weight of raisins she uses to make the breakfast cereal

Answers

Answer:

weight of raisins : 40

Step-by-step explanation:

nuts : raisins : oats

3:2:5= 60: ? : ?

60÷3 = 20

raisins : 2×20 = 40

Which one is correct?

Answers

Your answer would be C because the chance with being theoretical would be 50/50 split and with it being experimental it’s 62% so it’s 12 greater than the theoretical way, hope I could help and consider marking brainalist :)

A middle school has 220 students in each grade 6,7,8.The librarian wants to know which books are the most popular among the students in her school.

Answers

Answer:

?

Step-by-step explanation:

the choices, the question?

NOOOO LINKS FILES
At a contest, each diver was scored on a 1-10 scale for each of 8 divee. This data set shows the scores earned by one of the divers
83 8 6 8 834
Which value represents the median of the data set?
A.5
B.6
C.7
D.8

Answers

Answer:

6 is the median

Step-by-step explanation:

The median is the same as the number in the middle, and the number in the middle is 6.

Help please!!!!!!!!!! Need ASAP!! Thank you!

Maria can stuff envelopes twice as fast as her friend James. Together they can stuff 6750 envelopes in 4.5 hours. How long would it take each of them working alone? Which of the following equations could be used to solve this problem?

Answers

I thinks it's the last one

hope this helps

Answer:

B. 4.5/t + 4.5/(2t) = 1

Step-by-step explanation:

Work = rate*timeMaria's rate = 6750/tJames's rate = 6750/2t

Their rate when working together:

6750/t + 6750/(2t) = 6750/4.5 ⇒ 1/t + 1/(2t) = 1/4.5 ⇒4.5/t + 4.5/(2t) = 1

Correct choice is B

GIVING OUT BRAINLIEST ANSWER !! PLS HELP ME OUT !! (last minute)

Answers

Answer:

.764

Step-by-step explanation:

do it on a calculator (TI84)

Answer:

45.6°

Step-by-step explanation:

take the inverse cosine of 7/10: [tex]cos^{-1}(\frac{7}{10})[/tex]

plug it into a graphing calc and you get ≈ 45.573°, they want 1 decimal place so it would be ≈ 45.6°

Find the missing side of each right triangle (((((Pythagorean’s Theorem))))))))

Answers

Answer:

3

Step-by-step explanation:

36-27 = 9

[tex]\sqrt{9} = 3[/tex]

add 2 please add
[tex]2 \frac{3}{4} + 5 \frac{4}{5} = [/tex]

Answers

Answer:

Step-by-step explanation:

19/4 + 29/5

2.75 + 5.8

= 8.55

plz help for a brainly

Answers

Answer:

364yd^2

Step-by-step explanation:

LxWxH

Answer:

its 364

Step-by-step explanation:

you do length times width times height

Which triangle side lengths form a right triangle? Choose all that apply.

➪ 5, 6, 7
➪ 6, 8, 14
➪ 8, 15, 17
➪ 10, 12 15
➪ 15, 20, 15
➪ 16, 18, 20​

Answers

Your answer would be C (8,15,17) and E (15,20,15) or is it 25?

Step-by-step explanation:

:)

A farmer wants to know the effect of using various amounts of fertilizer in relation to the yield of his crops. Be subdivided a portion of his land into 10 separate but essentially equal plots. He divided the land so that all of the plots had equal exposure to sun, rain, and other environmental conditions. He randomly selected 2 of the 10 plots and spread 2 pounds of fertilizer over each of them. Then he randomly selected 2 of the remaining plots and spread 3 pounds of fertilizer over each of them. He continued with the last sets of plots in the same manner, spreading 4, then 5, then 6 pounds of fertilizer over each of them. Below is a computer output for linear regression of amount of fertilizer versus yield for the 10 plots of land.

Predictor Coef SE Coef T P
Constant 10.100 0.7973 12.67 0.000
Fertiz 1.150 0.1879 6.12 0.000

Required:
What is the equation of the least squares regression line from this sample?

Answers

Answer:

The equation of line is

[tex]\text{yield}=1.15\times \text{fertilizer}+10.1[/tex]

Step-by-step explanation:

The general equation of line is given as

[tex]y=mx+b[/tex]

where

y is the dependent variable which is yield in this case.

x is the independent variable which is fertilizer in this case

m is the coefficient of the fertilizer whose value is 1.150 from the given values.

b is the constant whole value is 10.100 from the given values.

Thus the equation becomes.

[tex]\text{yield}=1.15\times \text{fertilizer}+10.1[/tex]

1. You are rolling a pair of dice. What's the probability of getting different numbers on both dice?

Answers

Answer:

5/6

Step-by-step explanation:

Total outcomes:

6*6 = 36

Outcomes with same numbers on both dice:

6

Outcomes with different numbers on both dice:

36 - 6 = 30

Probability of different numbers on both dice:

30/36 = 5/6

What is the answer to this question?

Answers

Answer:

I dont know

Step-by-step explanation:

im trying to get brainly points lol

What is factor for 7x^2-21-280

Answers

7x^2 − 21 −280
= 7x^2 + −21 + −280

Then combine like terms:
= 7x^2 + −21 + − 280
= (7x^2) + ( − 21 + − 280)
= 7x^2 + −301
7

2

2
1

2
8
0
7
x
2

21

280
7x2−21−280
7

2

3
0
1

Type your answer and describe how
you found the answer
ROSS is a museum tour
guide at the Art Museum.
He charges $35 per person
for a 1 hour tour. He
typically has 54 people on
tours during the week. His
expenses for the week are
approximately
$108.63.
What is the amount of
profit that Ross will make?

Answers

Answer:

Ross's profit it 1,781.37

Step-by-step explanation:

$35 per person and 54 people= 35x54=1890

Profit= the amount of money he makes after his expenses.

1890-108.63=1781.37

Examine the figure of two parallel lines cut by a transversal.



What is the value of x?

Answers

Answer:

x=17

Step-by-step explanation:

The angles present are Alternative interior angles. That means that they are congruent. Meaning 4x+7 = 75. To solve for 7, you subtract 7 from both sides. That leaves you with 4x=68. Then you divide both sides with 4. Then you get x=17.

Hope this helps!

BTS!!

Answer:

x = 17

Step-by-step explanation:

75° and (4x + 7)° are alternate interior angles.

If two lines are cut by a transversal, then the alternate interior angles are congruent.

75 = 4x + 7

=> 4x = 68

=> x = 17

Which expressions are equivalent to 3 1/4 - (- 5/8)?

Answers

Answer:

3.875

Step-by-step explanation:

In order to solve for the variable in the equation 2 (x + 3) + 5 x = 3 (2 x minus 1), Jaleesa begins by applying the distributive property, then combines like terms. Which equation is the result of these steps?
7 x + 6 = 6 x minus 3
2 x + 6 + 5 x = 6 x minus 3
2 x + 3 + 5 x = 6 x minus 1
7 x + 3 = 6 x minus 1

Answers

Answer: 7 x + 6 = 6 x minus 3

Step-by-step explanation:

2 (x + 3) + 5 x = 3 (2 x minus 1)Now you distribute.2(x) + 2(3) = 2x+6And 3(2x) minus 3(1) = 6x minus 32x+6+5x = 6x minus 3Then combine like terms2x +5x=7x and there are no other like terms on either side of the equation.7x+6= 6x minus 3

Answer:7x+6=6x-3

Step-by-step explanation:

What is the theoretical probability that the spinner below will land on 6 if someone spins it 48 times?

Answers

Answer:

1/4 or 12*

Step-by-step explanation:

There are 8 possibilities.  2 of them are 6.

2/8=1/4

1/4 of 48 is 12

*The theoretical probability doesn’t change no matter how many times you spin the spinner.  It will always be 1/4.  (Or 0.25, or 25%). That could be what they’re asking.  If you spun it 48 times, it would probably land on a six 12 times.  That could also be what they’re asking for.  12:48 = 1:4.

please help me. Will mark u brainlyist.... Please don't put a randome answer if u don't know.

Answers

Answer:

105

Step-by-step explanation:

< 7 is also 105- they are alternate exterior angles

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