A tire manufacturer is interested in testing the fuel economy for two different tread patterns. Tires of each tread type are driven for 1000 miles on each of 18 different cars. In a separate experiment, 18 cars were outfitted with tires with tread type A, and another 18 were outfitted with tires with tread type B. Each car was driven 1000 miles. The cars with tread type A averaged 23.95 mpg, with a standard deviation of 1.79 mpg. The cars with tread type B averaged 22.19 mpg, with a standard deviation of 1.95 mpg. Let μX represent the population mean mileage for tread type A and let μY represent the population mean mileage for tread type B.


Required:

Find a 99% confidence interval for the difference μXâμY. Round the answers to three decimal places.

Answers

Answer 1

Using the t-distribution, it is found that the 99% confidence interval for the difference is (0.058, 3.462).

We are given the standard deviation for the samples, hence, the t-distribution is used to solve this question.

The standard errors are given by:

[tex]s_A = \frac{1.79}{\sqrt{18}} = 0.4219[/tex]

[tex]s_B = \frac{1.95}{\sqrt{18}} = 0.4596[/tex]

For the distribution of differences, the mean and the standard error are given by:

[tex]\overline{x} = \mu_A - \mu_B = 23.95 - 22.19 = 1.76[/tex]

[tex]s = \sqrt{0.4219^2 + 0.4596^2} = 0.6239[/tex]

The interval is given by:

[tex]\overline{x} \pm ts[/tex]

The critical value for a two-tailed 99% confidence interval with 18 + 18 - 2 = 34 df is t = 2.7284.

Then:

[tex]\overline{x} - ts = 1.76 - 2.7284(0.6239) = 0.058[/tex]

[tex]\overline{x} + ts = 1.76 + 2.7284(0.6239) = 3.462[/tex]

The 99% confidence interval for the difference is (0.058, 3.462).

For more on the t-distribution, you can check https://brainly.com/question/16162795


Related Questions

A group of 4 friends went out for a special dinner. the items they ordered are listed below
24.95+18.96+17.55+23.14+12.00=96.60
Part B: The four friends decided to split the bill evenly. How much does each friend owe

Answers

My friends the answer is 3.

  24.95 + 18.96 + 17.55 + 23.14 + 12.00 + 96.60

  4 divided by 12 is 3

       

when a company produces 5,000 units, variable costs are $35 per unit and total cost in $200,000. What is the total cost when the company produces 8,000 units? (both 8000 and 5000 units produced are within the relevant range.)

Answers

$320,000 is what the company produces with 8000 units.-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

Can anyone answer this?

Answers

Answer:

  ∠AMB = 103°

Step-by-step explanation:

The sum of angles in ∆AMB is ...

  (∠A)/2 +(∠B)/2 + ∠AMB = 180°

  ∠AMB = 180° -(∠A +∠B)/2 = 180° -(58° +96°)/2

  ∠AMB = 103°

A special cereal mixture contains rice and wheat in the ratio of 2:3. If a bag of the mixture contains 3 pounds of rice, how much wheat does it contain?

Answers

4.5 pounds I believe

solve pls brainliest

Answers

1: 64 : -8 x -8 2: -27 : -3 x -3 x -3
I hope this is correct

Answer:

-8^2=1/64 and -3^3=1/27

Step-by-step explanation:

I appreciated if you mark me as brainliest


17) Which number is located the same distance on
a number line from -5 as 3 is?

Answers

Answer: -13

Step-by-step explanation:

I know that the distance between -5 and 3 is 8 so I subtracted 8 from the negative 5 so it would be the same distance and I got -13

Answer:

-13

Step-by-step explanation:

In the expression -3×+4y-2 what are the variables

Answers

Answer:

x and y are the variables

A company makes 140 bags.
41 of the bags have buttons but no zips.
48 of the bags have zips but no buttons.
25 of the bags have neither zips nor buttons.
A bag is selected at random.
What is the probability that the bag has buttons?

Answers

Answer:

41/140 or approximately 29.29%

Step-by-step explanation:

Divide 41 by 140 to get 0.29285714285, and round it to the nearest hundredths.

Answer:

Step-by-step explanation:

b= buttons

z= zips

b∩z'=41

b'∩z=48

b'∩z'=25

b=?

b= b∩z+b∩z' (law of total probability)

140=b∩z+b∩z'+b'∩z+b'∩z'  (if this is confusing draw a venn diagram)

140=b∩z+41+48+25

b∩z=26

26+41= 67

67/140= .478571429

4. Find the sum of all the numbers from 100 to 199 that are not divisible by 13.
What is the formula for
this?

Answers

There are 100 numbers in the range 100-199. Find the smallest and largest multiple of 13 in this range. We have

104 = 8•13

195 = 15•13

so there are 15 - 8 + 1 = 8 multiples of 13 between 100 and 199.

Then the sum we want is

[tex]\displaystyle \sum_{k=100}^{199} k - \sum_{\ell=8}^{15}13\ell[/tex]

or equivalently,

(100 + 101 + 102 + … + 199) - 13 (8 + 9 + … + 15)

To compute these sums, recall the following formula:

[tex]\displaystyle \sum_{i=1}^n i = 1 + 2 + 3 + \cdots + n = \frac{n(n+1)}2[/tex]

Then

[tex]\displaystyle \sum_{k=100}^{199} k = \sum_{k=1}^{199} k - \sum_{k=1}^{99} k = \frac{199\cdot200}2 - \frac{99\cdot100}2 = 14,950[/tex]

and

[tex]\displaystyle \sum_{\ell=8}^{15} 13\ell = 13 \left(\sum_{\ell=1}^{15} \ell - \sum_{\ell=1}^7 \ell\right) = 13 \left(\frac{15\cdot16}2 - \frac{7\cdot8}2\right) = 1,196[/tex]

which means the sum we want is 14,950 - 1,196 = 13,754.

TOT ROLIOS
-: Study Guide Ratios (Quiz 1)
Arroz Con Leche
Arroz con leche is a creamy dessert from Mexico and Spain.
Nia wants to use 6 cups of rice.
1. How much of each ingredient does she need?
Ingredients
Serves 4 people
2 cups of rice
4 cups of milk
.
cups of rice
.
cups of milk
į cup of sugar
cups of sugar
i handful of raisins
1 cinnamon stick
handfuls of raisins
cinnamon sticks
How many people will this larger batch of Arroz Con Leche serve?

Answers

Answer:

If Mia wants to use 6 cups of rice, she would need to multiply the amount of each ingredient by 3, because the original 2 cups times 3 is the 6 cups she wants to use. So the new amount for the recipe would be this:

6 cups of rice

12 cups of milk  

1 cup of sugar  

3 handful of raisins

3 cinnamon sticks

When asking how many this will serve, we also multiply by 3 the original amount of people which is 4 to get 12 servings of Arroz con leche

A rectangular garden is 16 feet wide. Its length is 8 feet more than twice the width. What is the area of the garden?

Answers

Answer:

640 ft²

Step-by-step explanation:

Hi there!

We're given:

Width = 16

Length = 2 x Width + 8

Solve for the length:

l = 2(16)+8

l=32+8

l=40

Therefore, the length of the garden is 40 ft.

To find the area, multiply the length and width:

A = lw

A = (16)(40)

A = 640 ft²

I hope this helps!

$49.95 gloves 5 1/4 % markup

Answers

Answer:

1234567891011121314151617181920

Find the area of the shaded shape

Answers

Answer:

105

Step-by-step explanation:

yeah-ya............. right?

DeAnna Worley is the office manager at Central
BioEnergy. She is married with one dependent. Her annual
graduated state income tax is $3,520. What is her semimonthly
salary

Answers

Answer:

67 i thing so if it wrong sorry and ill answer  it again ight

Step-by-step explanation:


Use the quadratic formula to find the solution to the quadratic equation given
below.
x2-x* 1-0
D A
1+
14
2
1-IS
X =
D
B. x-
= -2
O c. x = 3
-
-1+
D.x =2 1-O
E.1 4x=
.
OF.x
2

Answers

Answer:

x=-1/2

Step-by-step explanation:

using almighty formula

x= -b+or-√b²-4ac/2a

x=-1+ or -√-1+4(1)(1/4) divided by 2(1)

x=-1+ or -√-1+1 divided 2

x=-1+0 divided by 2

x=-1/2

5/8 Divided by 6 5/6

Answers

Answer:

15/164

Step-by-step explanation:

5/8 ÷ 6 5/6 = 5/8 ÷ 41/6

                   = 5/8 x 6/41

                   = 30/328

                   = 15/164

Round your answer to the Nearest tenth

Answers

v = (8x7) / 17
v = 56 / 17
v = 3.294
v = 3.3

Answer:

3.3 or [tex]\frac{56}{17}[/tex]

Step-by-step explanation:

v/7 = 8/17                    

Cross multiply ... v times 17 & 7 times 8

17v = 56

Divide both sides by 17

v = 56/17

Keep your answer as a fraction OR

Convert to a decimal : 3.3

4(x-3) < x+3, Where x ∈ W
Please help me​

Answers

[tex]\large\underline{\sf{Solution-}}[/tex]

Given:

[tex]\rm\longmapsto 4(x-3)<x+3, x\in \mathbb{W}[/tex]

[tex]\rm\longmapsto 4x-12<x+3[/tex]

[tex]\rm\longmapsto 4x-12-x<x+3-x[/tex]

[tex]\rm\longmapsto 3x-12<3[/tex]

[tex]\rm\longmapsto 3x-12+12<3+12[/tex]

[tex]\rm\longmapsto 3x<15[/tex]

[tex]\rm\longmapsto \dfrac{3x}{3}<\dfrac{15}{3}[/tex]

[tex]\rm\longmapsto x<5, x\in\mathbb{W}[/tex]

[tex]\large\underline{\sf{Answer-}}[/tex]

Therefore:

[tex]\rm\longmapsto x=\{0,1,2,3,4\}\ \ \ [/tex]

Which expression represents the number of thirds in 1

Answers

Answer:

A third is written as ¹/₃

Step-by-step explanation:

The way to understand this is the number on the bottom is the number of pieces being divided into;

So ¹/₃ is 1 whole divided into 3 parts;

So, you need 3 ¹/₃ parts to make a whole

[tex]a \ * \ \frac{b}{c} = \frac{ab}{c} \\\\ 3 \ * \ \frac{1}{3} = \frac{3 \ * \ 1}{3} \\\\ = \frac{3}{3} \\\\ = 1[/tex]

From a group of 15 men and 12 women, how many ways can you select a group of 2?
Answer:

Answers

The total number of ways this can be done together is 105 × 66 = 6930

This is a combination question question it has to do with selection.

In order to group 2 men from 15 men, this can be expressed using the combination formula as shown;

15C2 = 15!/(15-2)!2!

15C2 = 15!/13!2!

15C2 = 15×14/2

15C2 = 105 ways

Similarly in order to group 2 women from 12 men, this can be expressed using the combination formula as shown;

12C2 = 12!/(12-2)!2!

12C2 = 12!/10!2!

12C2 = 12×11/2

12C2 = 66 ways

The total number of ways this can be done together is 105 × 66 = 6930

Learn more about combination here: https://brainly.com/question/14492965

The graph of y=⅔ x - 12 intersects the y-axis at Q (0, -12) and is perpendicular to a line joining Q to the point P ( x , 0). Find x

Answers

They will go over point 3,0 and /4,9 then

CAN SOMEONE PLS HELP ME ILL GIVE YOU BRAINLIST IF YOU GET IT RIGHT

Answers

3rd option: A middle school student it more likely to own a phone than an elementary school student


I NEED HELP W THIS ASAP!!!!!

Answers

Answer:

[tex]18[/tex]

Step-by-step explanation:

[tex] \frac{28}{14} = 2 \\ \frac{36}{x} = 2 \\ x = \frac{36}{2} \\ = 18[/tex]

Christine made $143 for 11 hours of work.
At the same rate, how many hours would she have to work to make $221?

Answers

Answer:

17

Step-by-step explanation:

Write each value in standard form.
1. 507 thousandths
2. 5 and 6 thousandths
3. 9 and 62 thousandths​

Answers

Answer:

1. 0.507

2. 5.006

3. 9.062

Step-by-step explanation:

If a value has “thousandths” in the question, the decimal place goes 4 places to the left: ex. 0.007.

You invest AED 5000 in a saving account that earns 4% interest each year. If you do not use the account for a year, how much money will you have in your account after a year?

Answers

9514 1404 393

Answer:

  AED 5200

Step-by-step explanation:

The interest in the first year will be ...

  I = Prt . . . . principal P invested at rate r for t years

  I = 5000×0.04×1 = 200

The account will have AED 5200 in it after a year.

Repost
A group of tourists are on a three-day hiking trip. They hike ⅛ of the trail on the first day. On the second day, they hike 4/7 of the remaining distance. On the third day, they hike 1/3 of the remaining distance, plus the final 8 km. How many kilometers long is the trail?

Answers

Answer:

You told me to resolve this question

Hoping to lure more shoppers downtown, a city builds a new public parking garage in the central business district. The city plans to pay for the structure through parking fees. During a two-month period (44 weekdays), daily fees collected averaged $126, with a standard deviation of $15. a) What assumptions must you make in order to use these statistics for inference

Answers

The assumptions required for making inference about a population using sample data include ;

The 10% condition, sample size must not be more than 10% of the population size

Data should be approximately normal with sample size, n being greater than 30 (n 30).

The sample selection must be independent, as the outcome of a certain trial must not depend on the outcome of another.

Learn more : https://brainly.com/question/25609474

A shoe box in the shape of a rectangular prism has these dimensions 14in,8 1/2in,4 3/4inwhat is the volume

Answers

Answer:

565.25 inches cubed

Step-by-step explanation:

14*(8 + 1/2)*(4 + 3/4)=565.25 inches cubed

a. 7 + 3 x 2 + 4 = 25
7+ 3x2+4 =25

Answers

Answer:

False

Step-by-step explanation:

The sides are not equal.

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