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Zinaida [17]
2 years ago
8

A tooth-whitening gel is to be tested for effectiveness. A group of 85 adults have volunteered to participate in the study. Of t

hese, 43 are to be given a gel that contains the tooth-whitening chemicals. The remaining 42 are to be given a similar-looking package of gel that does not contain the tooth-whitening chemicals. A standard method will be used to evaluate the whiteness of teeth for all participants. Then the results for the two groups will be compared. 1. After the treatment period, compare the whiteness of the 43 treated adults. 2. A placebo is not being used. 3. After the treatment period, compare the whiteness of the two groups. 4. Randomly select 85 adults to be given the treatment gel. 5. The remaining 42 adults receive the placebo gel. 6. Randomly select 43 adults to be given the treatment gel.
Mathematics
1 answer:
Lina20 [59]2 years ago
5 0

Answer:

(a) 3, 5 and 6

Step-by-step explanation:

In the experiment, 43 are to be given a gel that contains the tooth-whitening chemicals while the remaining 42 are to be given a placebo. Therefore, a placebo is used.

The 43 that will receive the gel are to be selected randomly.

After the experiment, the whiteness of the two groups will be compared to see the effect of the gel.

Therefore for the experiment to be completely random,  3, 5, and 6 apply.

(b)

For the experiment to be double-blind, the researchers who will evaluate the whiteness and interact with the subjects, and the subjects would not know which subjects received either the whitening gel or the placebo.

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You are in a bike race. When you get to the first checkpoint, you are 25 of the distance to the second checkpoint. When you get
Rom4ik [11]

Question:

You are in a bike race. When you get to the first checkpoint, you are 2/5 of the distance to the second checkpoint. When you get to the second check point, you are 1/4 of the distance to the finish. If the entire race is 40 miles, what is the distance between the start and the first check point?

Answer: 4 miles

Step-by-step explanation:

Let distance between start to first checkpoint = x

First checkpoint to second checkpoint = 2/5 of x

Distance of start to checkpoint 1 = ( 2/5 of start to checkpoint 2)

Distance of start to checkpoint 2 = (1/4 of start to finish)

If start to checkpoint 2 = 1/4 of start to finish

Then,

Distance of start to checkpoint 1 = ( 2/5 * 1/4 of start to finish)

Distance of start to checkpoint 1 = 2/20 of start to finish = 1/10 of start to finish

Entire race = 40 miles = distance from start to finish

1/ 10 of 40

= ( 1/10) × 40

= 4 miles

6 0
2 years ago
Alinethatincludesthepoint(2, 7)has slope of 5 . what isitsequationin slope -intercept form
Vesna [10]
10? Im not sure though my friend just told me it was 10
8 0
1 year ago
What is not a pair of equivalent fractions for 5/8 and 1/2
n200080 [17]
Two fractions equivalent to each: Just divide or multiply both top AND bottom by the same number.<span>
5/6: 10/12 OR 15/18 
15/30: 5/10 OR 1/2 
45/60: 8/12 OR 4/6 

Rewrite each pair or fractions with common denominator: Find the difference between the two bottom numbers, and multiply top and bottom number. 

5/8 and 3/4: 4X2=8, 3X2=6. So, 5/8 and 6/8. 
2/5 and 1/2: 2/5 and 2.5/5 
9/9 and 5/7: 9/9 and ~5.7/9 

Rewrite each in simple form: Find greatest common factor and divide. 

9/54: 1/6 
20/40: 1/2 
100/110: 10/11 

Are these fractions equivalent? 
No. 5/1 and 5/5 are, because they are both 5 wholes. 1/5 is not because it is a fifth of a whole. 


In what situation can you use multiplication to find equivalent fractions? 
I'm sorry but I do not understand this question. 
</span>Source(s):<span>I hope I  helped, seeing as I have graduated with a math degree.</span>
7 0
2 years ago
In △ABC,c=71, m∠B=123°, and a=65. Find b.<br><br> A. 101.5<br> B. 117.8<br> C. 123.0<br> D. 119.6
tia_tia [17]

Answer:

Option D

Step-by-step explanation:

The questions which involve calculating the angles and the sides of a triangle either require the sine rule or the cosine rule. In this question, the two sides that are given are adjacent to each other the given angle is the included angle. This means that the angle B is formed by the intersection of the lines a and c. Therefore, cosine rule will be used to calculate the length of b. The cosine rule is:

b^2 = a^2 + c^2 - 2*a*c*cos(B).

The question specifies that c=71, B=123°, and a=65. Plugging in the values:

b^2 = 65^2 + 71^2 - 2(65)(71)*cos(123°).

Simplifying gives:

b^2 = 14293.0182932.

Taking square root on the both sides gives b = 119.6 (rounded to the one decimal place).

This means that the Option D is the correct choice!!!

8 0
2 years ago
D(-3+x)=kx+9 solve for x
Gnesinka [82]

d(-3 + x) = kx + 9

  • Distribute d inside the parentheses.

-3d + dx = kx + 9

  • Subtract kx from both sides.

-3d + dx - kx = 9

  • Add 3d to both sides.

dx - kx = 9 + 3d

  • Factor x out of dx - kx.

x(d - k) = 9 + 3d

  • Divide both sides by d - k.

x = \frac{9+3d}{d-k}

  • If you want to simplify this even more, factor 3 out of the numerator.
<h3>x = \frac{3(d + 3)}{d-k}</h3>
5 0
2 years ago
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