A company wants to compare two washing detergents (Brands A and B) to see which best keeps colors from fading. Twenty new, identical red t-shirts will be used in the trials. Ten t-shirts are washed 15 times with Brand A in warm water. The other 10 t-shirts are washed with Brand B in cold water. The amount of fading is rated on a 0 to 100 scale, and the mean for the t-shirts washed in Brand A is compared to the mean for the others. Is this a good experimental design

Answers

Answer 1

Answer:

No, because water temperature is confounded with brand of detergent.

Step-by-step explanation:

There is a very possible chance of allowing a third or confounding variable to have creepwd into the research. The aim was to investigate which of two detergents prevents color from fading. Hence, the test for both detergents should be carried out under the same research condition. However, with adoption of different water temperature for each of detergent A and B, there may be a relationship between fading and water temperature which is not what are trying to investigate. This difference in temperature will thus cause a spurious relationship in our research. Hence, water temperature has been confounded with detergent brand, making this experimental design a bad one.


Related Questions

I NEED PLEASE IT WOULD REALLY HELP ME ALOT !!


NO LINK OR ZOOMS

Answers

Answer:

Step-by-step explanation:

For positive acute angles A and B, it is known that cos A= 20/29 and tan B= 11/60. Find the value of cos(A + B) in simplest form.

Answers

Answer:

[tex]\displaystyle \cos(A + B) =\frac{969}{1769}[/tex]

Step-by-step explanation:

We are given that:

[tex]\displaystyle \cos A=\frac{20}{29}\text{ and } \tan B=\frac{11}{60}[/tex]

Where A and B are positive acute angles.

And we want to find cos(A + B).

Recall that cosine is the ratio of the adjacent side to the hypotenuse. Using this information, find the opposite side with respect to Angle A:

[tex]o=\sqrt{29^2-20^2}=21[/tex]

Tangent is the ratio of the opposite side to the adjacent side. Find the hypotenuse with respect to Angle B:

[tex]h=\sqrt{11^2+60^2}=61[/tex]

In summary:

With respect to Angle A, the adjacent side is 20, opposite is 21, and the hypotenuse is 29.

With respect to Angle B, the adjacent side is 60, the opposite is 11, and the hypotenuse is 61.

We can rewrite our expression as:

[tex]\displaystyle \cos(A+B)=\cos A\cos B-\sin A\sin B[/tex]

Using the above information, substitute in the appropriate values. Note that since A and B are positive acute angles, all trigonometric values will be positive. Hence:

[tex]\displaystyle \cos(A + B)=\left(\frac{20}{29}\right)\left(\frac{60}{61}\right)-\left(\frac{21}{29}\right)\left(\frac{11}{61}\right)[/tex]

Simplify:

[tex]\displaystyle \cos(A + B) =\frac{1200-231}{1769}=\frac{969}{1769}[/tex]

find the value of x pls help

Answers

Answer:

x = 15°

Step-by-step explanation:

First Identify the angle of x by subtracting 180° - 120° = 60°

Always remember when you see a straight line the line measures 180°

So the angle of x = 60° but not the value of x so use the given equation to find the value of x

3x + 15 = 60°

3x  - 15 = -15°

3x = 45

x = 15°

A psychologist is interested in determining whether a new treatment for depression improves (decreases) depression scores. She randomly assigns 30 subjects to the treatment and 30 subjects to the control. At the conclusion of the study she uses an independent t-test to evaluate whether the groups differ on a widely used depression scale that ranges between 0 and 30. The treatment group mean is 18 and the control group mean is 22. What is the null hypothesis for the analysis

Answers

Answer:

Mean Hypothesis is Mean values of the treatment and the control group is not equal

Step-by-step explanation:

The null hypothesis is mostly the problem statement.

Here the problem statement is

To check whether there is a difference in treatment result of two groups of patient; one which has received the treatment and the other is the control group.

Thus, the null hypothesis is

H0 - Mean values of the treatment and the control group is not equal

License plates are made using 2 letters followed by 4 single digits. If any letter can be only used once but the digits can be repeated how many plate numbers are available?

Answers

Answer:

6,500,000

Step-by-step explanation:

Here, we first need to find all the possible selections for the code.

Then, we need to find the number of options for each one of these selections.

We have, 2 letters followed by 4 single digits.

There are 26 letters

There are 10 single digits.

For the first letter, we have 26 options.

For the second letter, we have 25 options (because one is already taken, and we can repeat that)

And for each one of the numbers, we have 10 options (we can repeat the numbers)

The total number of options for the code, is equal to the product of all the numbers of options for each selection, then the total number of possible plate numbers is:

C = 26*25*10*10*10*10 = 6,500,000

2. A guy wire is attached to the top of a radio tower to help support it. The tower
is 72 feet tall and the wire is attached to the ground 50 feet from the midline of
the tower. Find the length of the guy wire to the nearest foot.

Answers

72 feet’s and 50 feet’s equal 132 feet’s

Find the surface area of the cylinder.

Answers

Answer:

exact: 48pi cm^2

approximate: 150.8 cm^2

Step-by-step explanation:

SA = 2 * (pi)r^2 + 2(pi)rh

SA = 2 * pi * (3 cm)^2 + 2(pi) * 3 cm * 5 cm

SA = pi(18 cm^2 + 30 cm^2)

SA = 48pi cm^2

SA = 150.8 cm^2

It Says Minute At The End

Answers

Answer:

1.368

Step-by-step explanation: 1.14x1.2=1.368

1 in : 3 ft the center is 45 feet long and 28 feet wide

Answers

Answer:

Step-by-step explanation:

hey! i’ll give brainliest please help

Answers

Answer:

The 4th answer

Step-by-step explanation:

Answer:

D

hope this helps

have a good day :)

Step-by-step explanation:

3-1/3n< 6;n>-9 What is n???

Answers

Answer:

i don't understand your question, but i'll try to the best of my ability.

the answer to that is:

-8.33333333333

Step-by-step explanation:

let me break this down into a way you might understand.

1: 3-1=2

2: 2 divided by 3=0.66666666666.

3: i don't know if the "< 6;n>", was meant to be in the equation, so i just added the rest of it up.

if that's not right let me know. i'm pretty clueless sometimes, and this might just be a higher level of math that i don't know.

you're welcome though, (i suppose..) and have a great day.

Find the surface area of the pyramid represented by the net. 5.5 cm 5 cm 5 cm ​

Answers

Answer: I think the answer is 25 units squared

Step-by-step explanation:

A= l*w

A= 5*5

A=25^2

Answer: I think it's 80

Please someone help me ?!?!?

Answers

Answer:

I believe it would be B. SAS

Step-by-step explanation:

You have two sides and one angle that are congruent in both

Can someone please help me with this

Answers

Step-by-step explanation:

Therefore, 55+40+z=180

z=180-95

z=85

To get y,

z+y=180

85+y=180

y=95

Jeremy received $65 for his birthday and used part of it to buy 3 video games. The games cost the same amount, and he had $14 left. Write the equation used to determine how much each game cost.



A.3x + 14 = 65


B.3x - 14 = 65


C.65 - 3x = -14


D.14 - 3x = 65

Answers

A. Is your answer, if the games cost the same amount and he bought 3, that would give you 3x, the total is 65, and 14 is what was left. You would subtract 14 from the total, then divide by 3 to get x by itself.

Answer:

i believe the answer should be

Step-by-step explanation:

3x+14=65 which is telling you that 3 times a number which is unknown so we will call it x and add 14 equals 65. when you work it out you should get the total which is 65. so the way you work that out is you separate everything without an x to the right side of the equation which looks like 3x=65-14 then work it out subtract 14 from 65 and you get 3x=51 )which is total spent on 3 games. Then you divide 3x/3= 51/3 then the 3s cancel our so you have x=51/3 and when you work that out you get your answer x=17 which is the cost per game.

A circle in the xy-coordinate plane has the equation x2 + y2 +6y -4 = 0. If the equation of the circle is written in the form x2 + (y+k)2 = c.
where k and care constants, what is the value of K?

Answers

Answer:

k = 3

Step-by-step explanation:

Given

x² + y² + 6y - 4 = 0 ( add 4 to both sides )

x² + y² + 6y = 4

Using the method of completing the square

add ( half the coefficient of the y- term )² to both sides

x² + y² + 2(3)y + 9 = 4 + 9

x² + (y + 3)² = 13

with k = 3

Find the exact area of the shaded region.
120°
24 m
O A. (192 - 144)m2
OB. (192 - 14413 )m2
O C. (8 - 14413 )m?
O D. none of the above

Answers

Find the exact area of the shaded region.
120°
24 m
O A. (192 - 144)m2
OB. (192 - 14413 )m2
O C. (8 - 14413 )m?
O D. none of the above
The answer is 120 have a great day

Please help me solve!!

Answers

The answer is A just use the function

Helpppp
No links plz

Answers

Answer:

the third one ig

Step-by-step explanation:

sara spent $ 2.30 on sweets , $ 3.20 on a pencil and $ 9.15 on an excerise book . What steps would you use to find out much less than $ 15.00 sara spent

Answers

2.30 plus 3.20 and 9.15 is 14.65 .

What is the value of y in the diagram?
y
x
X-20

Answers

Answer:

x+x-20 = 180-90

2x-20 = 90

2x. =90+20

2x. =110

x. =55

y+55. =90

y. =90-55

y. =35

Gayle's hourly wage is $ 8.50. Gayle will be getting a 4% increase in pay at the end of the month. What will be Gayle's hourly wage after her pay increase?

Answers

Answer:

10.50

Step-by-step explanation:

Answer:

4 x 8.50

100

= 0.34

8.50 - 0.34 = 8.16

Step-by-step explanation:

a percentage is always over 100 so i 4 percent of 8.50 which gave me 0.34

Dont forget we are only focused on on the increase so we gotta subtract to make it normal from the original number which gives u 8.16...

Note dont forget it said an hour so multipy it by 1 hour since it said one hour which stills gives u the same answer

help me please this is urgent!

Answers

Answer:

D.

Step-by-step explanation: they can be different widths

The area of a parallelogram can be found by the
equation area = (b)(h)
Find the height of a parallelogram that has an area of
10 2 in2 and a base of Ži in.
SET
The height of the parallelogram is
inches.
I NEED THE ANSWE ASAP

Answers

The height = (7/2)

You take the answer and divide it by the base to get the height.
Same thing for base. You divide the answer by the height to get base.

Answer:

14

Step-by-step explanation:

just did it (don't search up mr hands)

The present ages of Ritu and Nitu are in the ratio15:8. After 10 years, their ages will be in the ratio 5:3 . Find their present ages.

Answers

Answer:

60 : 32

Step-by-step explanation:

Let x = Their present ages

Ritu : Nitu = 15x : 8x

After 10 years, their ages will be in the ratio 5:3

In 10 years

15x + 10 : 8x + 10 = 5 : 3

15x + 10 / 8x + 10 = 5/3

Cross product

15x + 10 * 3 = 8x + 10 * 5

45x + 30 = 40x + 50

45x - 40x = 50 - 30

5x = 20

x = 20/5

x = 4

Ritu : Nitu = 15x : 8x

Ritu : Nitu = 15 * 4 : 8 * 4

= 60 : 32

Ritu : Nitu = 60 : 32

PLEASE HELP!!!

ABC maps the outline of a new park. What is the area of the park?

the multiple choice answers are in the photo

Answers

Answer:

[tex]Area = 10[/tex]

Step-by-step explanation:

Given

[tex]A = (2,1)[/tex]

[tex]B =(4,7)[/tex]

[tex]C =(6,3)[/tex]

Required

The area of the park

The outline is a triangle and as such, the area is calculated using:

[tex]Area = \frac{1}{2}|(x_1y_2 - x_2y_1) + (x_2y_3 - x_3y_2) + (x_3y_1 - x_1y_3)|[/tex]

This gives:

[tex]Area = \frac{1}{2}|(2*7 - 4*1) + (4*3 - 6*7) + (6*1 - 2*3)|[/tex]

Using a calculator, we have:

[tex]Area = \frac{1}{2}|-20|[/tex]

Remove absolute bracket

[tex]Area = \frac{1}{2}*20[/tex]

[tex]Area = 10[/tex]

Enter the range of values for x:
B
15
2x - 10
С
48°
A
18
[?] Enter

Answers

Answer:   5 < x < 29

=========================================

Explanation:

Since AB is smaller than AD, this must mean the angle ACB is smaller than angle ACD. Note how these angles are opposite the sides mentioned.

So 2x-10 < 48

At the same time, 2x-10 is also larger than 0.

Overall, we can say 0 < 2x-10 < 48

---------

Let's solve for x

0 < 2x-10 < 48

0+10 < 2x < 48+10 ...... add 10 to all sides

10 < 2x < 58

10/2 < x < 58/2 ..... divide all sides by 2

5 < x < 29

you don’t have to tell me the answer i just dk what to do for this problem

Answers

Answ either

Step-by-step explanation:

I dont get this. please help

Answers

Answer:

Step-by-step explanation:

All of these are done exactly the same way so I will work out one of them for you, and you can follow my example to get the answers to the rest of them. I will do #5. The formula for this is

7(7 + x) = 8(8 + 13) and then solve the equation to find x:

49 + 7x = 168 and

7x = 119 so

x = 17.

Follow that pattern for each of your problems and you should be fine.

PLEASE HELP ME WITH THIS

Answers

here you go, should be right

Answer:

Plot your x,y points at (0,1) and (1,3)

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