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

What is the length of CD, given that figure ABCD is a rectangle?
B
13
С
10
A
D
O A. 26
O B. 10
O C. 13
O D. 20

Answers

Answer:

It'll be B.10

Step-by-step explanation:

Rectangles always have 2 side lower than the other2 . BC and AD are same length so they are both 13. BA and CB are the same length to It has to be 10.

Hope this helps :)

The answer would be B. 10


HELLOPPPPPPPPPPPPPPPP

Answers

Answer:

Hello!

Judging by the link you provided I have come up with the correct solution:

x= 61°

y= 29°

Step-by-step explanation:

I will link my work below:

The first step to finding the two solutions it to first identify one of them.

I chose to identify x first.

To identify the value of x in this problem you have to notice that the x value corresponds with the value "29°" to form a perfect right angle, being 90°.

Thus you can simply find the value of x by doing this formula:

x+29°=90°

You then subtract 29° from both sides to simplify, and you come up with the solution

x=61°

Now we need to find the value of y.

To find the value of y I noticed that again, like x, y corresponds with another variable (being x) to form a perfect right angle (90°).

The way I realized this is a perfect right angle is because, as you can see in the picture you provided, the y+x angle are alternate exterior angles with another angle that is 90°.

Thus you can assume that:

x+y=90°

x= 61°

61°+y=90°

You then subtract 61° from both sides to get:

y=29°

Rest of the options

Answers

The answer is D, the last one

given the sequence tn defined recursively below, find t4.

Answers

Answer:

[tex]t_4 = 20[/tex]

Step-by-step explanation:

The base case in the recursive function are:

[tex]t_1 = 1[/tex]

[tex]t_2 = 2[/tex]

The recursive case is equal to:

[tex]t_n = 2t_{n-1} + 3t_{n-2}[/tex]

So replace [tex]t_n[/tex] for [tex]t_4[/tex]:

[tex]t_4 = 2t_{3} + 3t_{2}[/tex]

In the new expression [tex]t_2[/tex] is a base case so you don't have to worry for that part, but [tex]t_3[/tex] is still the recursive case so evaluate again in [tex]t_n[/tex]

[tex]t_3 = 2t_{2} + 3t_{1}[/tex]

[tex]t_2[/tex] and [tex]t_1\\[/tex] are define as base cases so you replace for it's numbers:

[tex]t_3 = 2(2) + 3(1) = 7[/tex]

Now return to [tex]t_4[/tex] and replace for the new values:

[tex]t_4 = 2(7) + 3(2) = 14 + 6 = 20[/tex]

So the final answer is 20

Help help help help help math math please please pelsss

Answers

Answer:

Both of the angles will add up to 180 degrees so let’s make an equation.

5x-5+2x+10=180

First we collect like terms

5x+2x-5+10=180

Add them up

7x+5=180

Move the constant to the right

7x=180-5

7x=175

7x/7=175/7

x=25

So yes it’s true x=25.

Now we find the respective angles,

5x-5

5(25)-5

125-5

120

So angle one is 120 degrees.

2x+10

2(25)+10

50+10

60

So angle two is 60 degrees.

Now to check,

120+60=180

Step-by-step explanation:

15 mm
4. You are decorating the Red Cross logo
shown for a float in a parade.
a) The Red Cross logo consists of 5 congruent
squares. Find the area of the Red Cross logo.
+
b) You estimate that on average a red carnation
will cover 2 square inches and a red rose will cover
3 square inches. How many roses do you need to
cover the logo on the float?
36 in
c) You are on a budget. Carnations cost $1.00 and
roses cost $1.50. Should you cover the logo with
carnations or roses? Justify your answer.

Answers

Does it have to be a certain length

2.Một công ty sẽ bán N quyển sách sau khi chi tiêu x nghìn $ cho việc quảng cáo quyển sách
mới này, được cho bởi

2 N x x x = −   60 5 30

Answers

Answer:

that makes no sence we t guy

Step-by-step explanation:

hi hi hi hi hi hi h i hi h h ih  i hi hi i  hi h

Solve the given problem using Venn Diagram. Show your solution

A group of 50 students went on a tour in Palawan province Out of 50 students, 24 joined the trip to Coron; 18 went to Tubbataha Reef, 20 visited El Nido: 12 made a trip to Coron and Tubbataha Reef 15 saw the Tubbataha Reef and El Nido, 11 made a trip to Coron and El Nido: 10 saw the three tourist spots.

1. How many students went to Coron only?
2. How many students went to Tubbataha Reef only?
3. How many joined the El Nido trip only? 4. How many did not go to any of the tourist spot?

(Please kindly help me. I have answered this problem, but it seems not to be correct.)​

Answers

[tex] \red{ \rule{40pt}{555555pt}}[/tex]

Are the following two logical statements equivalent? p ∨ q q ∨ p

Answers

Answer:

Are the following two logical statements equivalent?

p

q

q

p

Can someone please me help

Answers

Answer:

Step-by-step explanation:

the answer is 1.1324

Jeanne is twice as old as her brother Mark. If the sum of their ages is 24, how old is Jeanne?

Answers

Jeanne is 16 years old


8 is half of 16, and 8 + 16 is 24

Can somebody plz report and ban CARDAA13 and CARIZASHINE

Answers

Answer:

what did they do?

Step-by-step explanation:

Round off the decimal 55.345 to 2 decimal places.​

Answers

Answer:

Step-by-step explanation:

55.345 is rounded off two places therefore, the hundreths place

the number next to 4 is 5 in the thousandths place. 5 is high and therefore 4 is changed to 5 and makes it 53.35

What is the equation in slope-intercept form of the line that passes through the points (-4, 6) and (-2,5) ?
y=20 - 8
y=-30+4
y=-22 +4
y = -x + 8

Answers

[tex](\stackrel{x_1}{-4}~,~\stackrel{y_1}{6})\qquad (\stackrel{x_2}{-2}~,~\stackrel{y_2}{5}) \\\\\\ \stackrel{slope}{m}\implies \cfrac{\stackrel{rise} {\stackrel{y_2}{5}-\stackrel{y1}{6}}}{\underset{run} {\underset{x_2}{-2}-\underset{x_1}{(-4)}}}\implies \cfrac{-1}{-2+4}\implies \cfrac{-1}{2}\implies -\cfrac{1}{2}[/tex]

[tex]\begin{array}{|c|ll} \cline{1-1} \textit{point-slope form}\\ \cline{1-1} \\ y-y_1=m(x-x_1) \\\\ \cline{1-1} \end{array}\implies y-\stackrel{y_1}{6}=\stackrel{m}{-\cfrac{1}{2}}[x-\stackrel{x_1}{(-4)}] \\\\\\ y-6=-\cfrac{1}{2}(x+4)\implies y-6=-\cfrac{1}{2}x-2\implies \underset{\textit{slope-intercept form}}{y=-\cfrac{1}{2}x+4}[/tex]

Calculate the volume of the pyramid. Round your answer to the nearest hundredth 10in 7in

Answers

Answer:

Place the numbers in their places. b=base h=height.

Step-by-step explanation:

|a| if a>0
Please help!

Answers

Answer:

Step-by-step explanation:

the absolute value bars mean we ignore the sign of the variable

As (a) is always positive for a>0,   |a| = a

For contrast, If the range were a<0 where (a) is always negative, then |a| = -a

Answer:

1/a > 0

Step-by-step explanation:

5. Use the point-slope formula to determine the equation of a line that passes through the points (1, 2) and (-2, 1).

Answers

Answer:

In point-slope form the equation is:

[tex]y - 2 = \binom{1}{3} \times (x - 1)[/tex]

A group of preschoolers has 63 boys and 27 girls. What is the ratio of boys to all children (lowest form)?

Answers

Answer:

7 boys to 10 all children

63:90= 7:10

Reasoning:
add up the total amount of preschoolers which is 90, and the amount of boys in the group of children which is 63. so it would be 63:90. 9 goes into both numbers. (63 divided by 9= 7. 90 divided by 9 is 10.) so the answer would be 7:10 in simplified form.

Emilia waited 11 minutes for the bus today. That is 4 minutes less than she waited yesterday. How long did Emilia wait for the bus yesterday?

Answers

11 minutes + 4 minutes more yesterday = 15 total minutes

Answer: 15 minutes

Answer:

Emilia waited 11 minutes wich was 4 minutes earlier so 11+4 because it was 4 miutes earlier so 11 minutes + 4 minutes = 15 minutes so this means Emilia wait 15 minutes for the bus yesterday

Step-by-step explanation:

(1/2)power 5=?? please help

Answers

[tex] \frac{1}{2} \: to \: the \: power \: of \: 5 \: is \: \frac{1}{32} or \: 0.03125 [/tex]

Answer:

[tex] \ {\boxed{ \tt ( \frac{1}{2}) ^{5} = \frac{1}{32} }}[/tex]

Step-by-step explanation:

[tex] \\ \tt( \frac{1}{2} )^{5} [/tex]

[tex] \\ \tt= \frac{ {1}^{5} }{ {2}^{5} } [/tex]

[tex] \\ \tt = \frac{1 \times 1 \times 1 \times 1 \times 1}{2 \times 2 \times 2 \times 2 \times 2} [/tex]

[tex] \\ \tt = \frac{1}{32} [/tex]

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

What is 5m + 5n where m = 10 and n = -5?

A. 25
B. 26
C. 62
D. 52

ADD EXPLANATION IF NECESSARY. TYSM! :D​

Answers

Answer:

A

Step-by-step explanation:

5 times 10= 50

5 times -5= -25

50-25=25

a ladder 7.5m long rests against a wall . the botton of ladder is 2.1m from the wall . calculate how far the ladder reaches up the wall.
PLEASE SOLVE THIS QUESTION!!​

Answers

Answer:

h = √(7.5² - 2.1²) = 7.2 m

Step-by-step explanation:

Pythagorean theorem

Please help!

The black graph is the graph of
y = f(x). Choose the equation for the
red graph.

Answers

Answer:

it would be c because its moved 2x up

Step-by-step explanation:

8m – 5 for m = 9 answer please

Answers

Answer:

= 67

Step-by-step explanation:

8m – 5 for m = 9

~Substitute

8(9) - 5

~Simplify

72 - 5

~Subtract

67

Best of Luck!

The answer is 67 I believe sorry if I’m wrong

A bakery sells 1/2 dozen cookies for $6.48. At this rate, how much would it cost for 3 dozen cookies?​

Answers

It would cost $38.88 for three dozen cookies
$38.88 is definitely the answer facts I had that problem too myself

A baker needs to arrange 487 cookies on plates.
Each plate can hold 8 cookies. How many plates will
the baker need

Answers

Based on the information given the number of plates that the baker will need is 61 plates.

Using this formula

Number of plates=Number of cookies arranged/Each plates number of cookies

Where:

Number of cookies arranged=487

Each plates number of cookies=8

Let plug in the formula

Number of plates=487/8

Number of plates=60.9

Number of plates=61 plates (Approximately)

Inconclusion the number of plates that the baker will need is 61 plates.

Learn more here:https://brainly.com/question/25130978

EXPLORE has 24 chess players. A team of 6 players, as well as 1 captain, will be chosen out of the 24 chess players (i.e. choose 7 players and then select the captain) How many different selections can be made?​

Answers

Answer:2422728

Step-by-step explanation:

п
What is the end behavior of the polynomial function?
1
8
B
4
2
6
2
2
8
B
X
-4
6
o As X->-co, then Y---
As X-→-00, then y0
As X-0, then y →-00
ne X -> then V -> 0

Answers

Answer:

The end behavior of a polynomial function is the behavior of the graph of f(x) as x approaches positive infinity or negative infinity

Step-by-step explanation:

hope this help

dont know if this is correct

The end behavior of the polynomial function is as x -> ∞, y -> -∞

How to determine the end behavior?

From the graph of the polynomial, we have the following highlight:

As x approached infinityThe function approaches negative infinity

The above highlights mean that:

As x -> ∞, y -> -∞

Hence, the end behavior of the polynomial function is as x -> ∞, y -> -∞

Read more about end behavior at:

https://brainly.com/question/1365136

#SPJ5

Relatively Simple Math, pls lend a hand. 50 points and Brainliest

Answers

I think the answer is A

Answer:

B. 192 miles in 3 hours

Step-by-step explanation:

Mr. Anderson's rate is:

480 / 7.5 = 64 mph

Given options, find rates and compare with the above number:

A. 120/2 = 60 mph, NoB. 192/3 = 64 mph, YesC. 100/1.5 = 66.66 mph, NoD. 240/3.25 = 73.85 mph, No
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